100+ Important Class 12 Computer Science Most Expected Questions

Looking for Class 12 Computer Science most expected questions? Get chapter-wise important Python, DBMS, File Handling and Networking questions for CBSE 2026 board exam preparation. Here we go!

Class 12 Computer Science Most Expected Questions

If you are preparing for the CBSE board exam, this collection of Class 12 Computer Science most expected questions will help you score high marks. These questions are carefully selected from previous year trends, important topics, and exam patterns.

This article includes chapter-wise important questions from Python, File Handling, Data Structures, DBMS, and Computer Networks for quick revision before the board exam.

Let us see the most expected questions computer science class 12 asked for 1, 2 and 3 marks questions.

Class 12 Computer Science Most Expected Questions Python revision tour

Let us start with python revision tour questions.

Python Revision Tour – MCQs\1 marks Questions

[1] State True or False – ‘Tuple is one of the datatypes of python having data in key-value pair.”

[2] State True or False “Python has a set of keywords that can also be used to declare variables.”

[3] Which of the following is not a valid python operator?

a) %

b) in

c) #

d) **

[4] What will be the output of the following python expression?

print(2**3**2)

a) 64

b) 256

c) 512

d) 32

[5] Which of the following is not a keyword?

a) eval

b) nonlocal

c) assert

d) pass

[6] Observe the given dictionary:

d_std={“Roll_No”:53,”Name”:’Ajay Patel’}

d_marks={“Physics”:84,”Chemistry”:85}

Which of the following statement will combine both dictionaries?

a) d_std + d_marks

b) d_std.merge(d_marks)

c) d_std.add(d_marks)

d) d_std.update(d_marks)

[7] What will be the output of the following python dictionary operation?

data = {‘A’:2000, ‘B’:2500, ‘C’:3000, ‘A’:4000}

print(data)

a) {‘A’:2000, ‘B’:2500, ‘C’:3000, ‘A’:4000}

b) {‘A’:2000, ‘B’:2500, ‘C’:3000}

c) {‘A’:4000, ‘B’:2500, ‘C’:3000}

d) It will generate an error

[8] What will be the output for the following expression:

not ((False and True or True) and True)

a) True

b) False

c) None

d) Null

[9] What will be the output for the following expression:

print(True or not True and False)

Choose one option from the following that will be the correct output after executing the above python expression.

a) False

b) True

c) or

d) not

[10] What will be the output of the given code?

s=’CSTutorial@TutorialAICSIP’

o=s.partition(‘Tutorial’)

print(o[0]+o[2])

a) CSTutorial

b) CSTutorialAICSIP

c) CS@TutorialAICSIP

d)Tutorial@TutorialAICSIP

[11] Select the correct output of the following python code:

str=”My program is program for you”

t = str.split(“program”)

print(t)

a) [‘My ‘, ‘ is ‘, ‘ for you’]

b) [‘My ‘, ‘ for you’]

c) [‘My’,’ is’]

d) [‘My’]

[12] Which of the following operations on a string will generate an error?

a) “PYTHON”*2

b) “PYTHON” + “10”

c) “PYTHON” + 10

d) “PYTHON” + “PYTHON”

[13] Kevin has written the following code:

d={‘EmpID’:1111,’Name’:’Ankit Mishra’,’PayHeads’:[‘Basic’,’DA’,’TA’],’Salary’:(15123,30254,5700)}   #S1

d[‘PayHeads’][2]=’HRA’                                                             #S2

d[‘Salary’][2]=8000                                                                  #S3

print(d)                                                                                    #S4

But he is not getting output. Select which of the following statement has errors?

a) S1

b) S2 and S3

c) S3

d) S4

[14] What will be the output of following expression in python?

print ( round (100.0 / 4 + (3 + 2.55) , 1 ) )

a) 30.0

b) 30.5

c) 30.6

d) 30.1

[15] Consider this statement: subject=’Computer’ + ‘ ’ + ‘Science 083’

Assertion(A): The output of statement is – “Computer Science 083”

Reason(R): The ‘+’ operator works as concatenate operator with strings and join the given strings

(A) Both A and R are true and R is the correct explanation for A

(B) Both A and R are true and R is not the correct explanation for A

(C) A is True but R is False

(D) A is false but R is True

Watch this video for more understanding:

MCQs Python Revision Tour

[16] Fill in the Blank:

The explicit ___________________ of an operand to a specific type is called type casting.

a) Conversion

b) Declaration

c) Calling of Function

d) Function Header

[17] Which of the following is not a core data type in Python?

a) Boolean

b) integers

c) strings

d) Class

[18] What will the following code do?

dict={"Exam":"SSCE", "Year":2022}
dict.update({"Year”:2023} )

a) It will create a new dictionary dict={” Year”:2023} and an old dictionary will be deleted

b) It will throw an error and the dictionary cannot be updated

c) It will make the content of the dictionary as dict={“Exam”:”AISSCE”, “Year”:2023}

d) It will throw an error and dictionary and do nothing

[19] What will be the value of the expression :

4+3%5

a) 2

b) 6

c) 0

d) 7

[20] Select the correct output of the code:

a= "Year 2022 at All the best"
a = a.split('2') 
b = a[0] + ". " + a[1] + ". " + a[3]
print (b)

a) Year . 0. at All the best

b) Year 0. at All the best

c) Year . 022. at All the best

d) Year . 0. at all the best

[21] Which of the following statement(s) would give an error after executing the following code?

S="Welcome to class XII"   # Statement 1
print(S)                   # Statement 2
S="Thank you"              # Statement 3
S[0]= '@'                  # Statement 4
S=S+"Thank you"            # Statement 5

a) Statement 3

b) Statement 4

c) Statement 5

d) Statement 4 and 5

[22] State true or false:

“A dictionary key must be of a data type that is mutable”.

[23] What will be the data type of p, if p=(15)?

a) int

b) tuple

c) list

d) set

[24] Which of the following is a valid identifier in python?

a) else_if

b) for

c) pass

d) 2count

[25] Consider the given expression:

‘5’ or 4 and 10 and ‘bye’

Which of the following will be the correct output if the given expression is evaluated?

a) True

b) False

c)’5’

d)’bye’

[26] Select the correct output of the code:

for i in "CS12":
     print([i.lower()], end="#")

a) ‘c’#’s’#’1’#’2’#

b) [“cs12#’]

c) [‘c’]#[‘s’]#[‘1’]#[‘2’]#

(d) [‘cs12’]#

[27] Which of the following Statement(s) would give an error after executing the following code?

d={"A":1, "B": 2, "C":3, "D":4}  #Statement 1
sum_keys =0                      #Statement 2
for val in d.keys():             #Statement 3
    sum_keys=sum_keys+ val       #Statement 4
print(sum_keys)

a) Statement 2

b) Statement 4

c) Statement 1

d) Statement 3

[28] What will the following expression be evaluated to in Python?

print(25//4 +3**1**2*2)

a) 24

b)18

c) 6

d) 12

[29] What will be the output of the following expression?

24//6%3 , 24//4//2 , 48//3//4

a) (1,3,4)

b) (0,3,4)

c) (1,12,Error)

d) (1,3,#error)

[30] What will the following expression be evaluated to in Python?
print(23 + (5 + 6)**(1 + 1))
(a) 529

(b) 144

(c) 121

(d) 1936

Watch this video for more understanding:

Python Revision Tour MCQ Computer Science Class 12

Python Revision Tour – 2 Marks Questions

1. a) Given is a Python string declaration:

message='FirstPreBoardExam@2022-23'

Write the output of: print(message[ : : -3].upper())

b) Write the output of the code given below

d1={'rno':21, 'name':'Rajveer'}
d2={'name':'Sujal', 'age':17,'class':'XII-A'}
d2.update(d1)
print(d2.keys())

Ans.:

Steps:

a)

F	i	r	s	t	P	r	e	B	o	a	r	d	E	x	a	m	@	2	0	2	2	–	2	3
-25	-24	-23	-22	-21	-20	-19	-18	-17	-16	-15	-14	-13	-12	-11	-10	-9	-8	-7	-6	-5	-4	-3	-2	-1
F			S			R			O			D			A			2			2			3

b)

Steps:

d2={‘name’:’Rajveer’, ‘age’:17,’class’:’XII-A’,’rno’:21, ‘rno’:21}

Now, d.keys() will return – dict_keys([‘name’,’age’,’class’,’rno’])

a) 322ADORSF
b) dict_keys(['name', 'age', 'class', 'rno'])

2. Predict the output of the following code:

dt=["P",10,"Q",30,"R",50]
t=0
a=""
ad=0
for i in range(1,6,2):
          t = t + i
          a = a + dt [i-1] + "@"
          ad = ad + dt[i]
print (t, ad, a)

Ans.:

Steps:

Iteration	Values
1	i=1 t=t+i t=0+1=1 a=””+”P”+”@”=P@ ad=0+10=10
2	i=3 t=1+3=4 a=’P@’+’Q’+’@’=P@Q@ ad=10+30=40
3	i=5 t=4+5=9 a=’P@Q@’+’R’+’@’ ad=40+50=90
4	For Loop Ends

9 90 P@Q@R@

3. Predict the output of the given code:

L=[11,22,33,44,55]
Lst=[]  
for i in range(len(L)):
   if i%2==1:
     t=(L[i],L[i]*2)
     Lst.append(t)
print(Lst)

Ans.:

Steps:

Iteration	Values
0	Condition False
1	i=1 t=(22,44) Lst=[(22,44)]
2	Condition False
3	i=3 t=(44,88) Lst=[(22,44),(44,88)]
4	Condition False
5	For loop Ends

[(22, 44), (44, 88)]

4. a) What will be the output of the following string operation?

str="PYTHON@LANGUAGE"
print(str[2:12:2])

b) Write the output of the following code.

data = [11,int(ord('a')),12,int(ord('b'))]
for x in data:
  x = x + 10
  print(x,end=' ')

Ans.:

Steps:

a)

P	Y	T	H	O	N	@	L	A	N	G	U	A	G	E
0	1	2	3	4	5	6	7	8	9	10	11	12	13	14
		T		O		@		A		G

b)

Iteration	Values
1	x=11 x=x+10=21
2	x=97 x=x+10=97+10=107
3	x=12 x=x+10=12+10=22
4	X=98 X=X+10=98+10=108

a) TO@AG
b) 21 107 22 108

5. Write the output of the following code and the difference between a*3 and (a,a,a)?

a=(1,2,3)
print(a*3)
print(a,a,a)

Ans.:

(1, 2, 3, 1, 2, 3, 1, 2, 3)
((1, 2, 3) (1, 2, 3) (1, 2, 3))

Difference:

a*3 will repeate the tuple 3 times where as (a,a,a) will repeat tuple 3 times into a separate tuple.

6. Predict the output

s="ComputerScience23"
n = len(s)
m=""
for i in range(0, n):
   if (s[i] >= 'a' and s[i] <= 'm'):
        m = m +s[i].upper()
   elif (s[i]>=’n’ and s[i]<=’z’):
        m = m +s[i-1]
   elif (s[i].isupper()):
        m=m+s[i].lower()
   else:
        m=m+’#’
print(m)

Ans.:

Steps:

C

o

m

p

u

t

e

r

S

c

i

e

n

c

e

2

3

if: a-n

M

E

C

I

E

C

E

elif: n-z

C

m

p

u

e

e

elif-upper

c

s

else

#

#

cCMmpuEesCIEeCE##

7. a) Given is a Python List declaration:

lst1=[39,45,23,15,25,60]

What will be the output of print(Ist1.index(15)+2)?

b) Write the output ot the code given below:

x=["rahul",5, "B",20,30]
x.insert(1,3)
x.insert(3, "akon")
print(x[2])

Ans.:

Steps:

a)

	39	45	23	15	25	60
Index	0	1	2	3	4	5
Index(15)				3+2=5

b)

	‘rahul’		5		‘B’	20	30
index	0	1	2	3	4	5	6
insert 1		3
insert 2				akon
x[2]			5

a) 5
b) 5

8. Predict the output of the python code given below:

st= "python programming"
count=4
while True:
   if st=="p":
      st=st[2:]
   elif st[-2]=="n":
      st =st[:4]
  else:
      count+=1
      break
print(st)
print(count)

Ans.:

p

y

t

h

o

n

p

r

o

g

r

a

m

m

i

n

g

if

False

elif

p

y

t

h

True

else

4+1=5

pyth
5

9. Predict the output:

myvalue=["A", 40, "B", 60, "C", 20]
alpha =0
beta = ""
gama = 0
for i in range(1,6,2):
  alpha +=i
  beta +=myvalue[i-1]+ "#"
  gama +=myvalue[i]
print(alpha, beta, gama)

Ans.: Steps are same as question 2.

9 A#B#C# 120

10. Rewrite the following code in python after removing all syntax error(s). Underline each correction done in the code.

Num=int(rawinput("Number:"))
sum=0
for i in range(10,Num,3)
   sum+=1
   if i%2=0:
          print(i*2)
   else:
          print(i*3)
          print (Sum)

Ans.:

Num=int(input("Number:")) #rawinput changed to input
sum=0
for i in range(10,Num,3):#Colon is missing to the end
   sum+=1
   if i%2==0:#equal sign is missing
          print(i*2)
   else:
          print(i*3)
print(Sum) # Inentation and S of sum should be small

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Watch the video Short answer questions
Computer Science Class 12
2 marks questions Python Revision Tour

Working with Functions Questions

In this topic, we are going to discuss the questions from the topic functions. Let us begin!

Working with Python Functions 2 marks Questions

From this topic working with functions output-based and error-based questions will be asked in 2 marks. So let us discuss working with python functions 2 marks questions. Here we go!

[1] Predict the output of the following python code:

data = [2,4,2,1,2,1,3,3,4,4]
d = {}
for x in data:
   if x in d:
     d[x]=d[x]+1
   else:
     d[x]=1
print(d)

Ans.:

data = [2,4,2,1,2,1,3,3,4,4]

x=2

if 2 in {}: 
  d[2]=1

if 4 in {2:1}:
   d[4]=1

if 2 in {2:1,4:1}:
   d[2]=d[2]+1=1+1=2

if 1 in {2:2,4:1}:
  d[1]=1

if 2 in {2:2,4:1,1:1}:
  d[2]=d[2]+1=2+1=3

if 1 in {2:3,4:1,1:1}:
   d[1]=d[1]+1=1+1=2

if 3 in {2:3,4:1,1:2}:
   d[3]=1

if 3 in {2:3,4:1,1:2,3:1}:
   d[3]=d[3]+1=1+1=2

if 4 in {2:3,4:1,1:2,3:2}:
  d[4]=d[4]+1=1+1=2

if 4 in {2:3,4:2,1:2,3:2}:
  d[4]=d[4]+1=2+1=3

Ans.:{2:3,4:3,1:2,3:2}

[2] Vivek has written a code to input a number and check whether it is even or odd number. His code is having errors. Rewrite the correct code and underline the corrections made.

Def checkNumber(N):
       status = N%2
       return
#main-code
num=int( input(“ Enter a number to check :")) 
k=checkNumber(num)
if k = 0:
   print(“This is EVEN number”)
else
   print(“This is ODD number”)

Ans.:

def checkNumber(N):
       status = N%2
       return status
#main-code
num=int( input(“ Enter a number to check :")) 
k=checkNumber(num)
if k == 0:
   print(“This is EVEN number”)
else:
   print(“This is ODD number”)

[3] Sameer has written a python function to compute the reverse of a number. He has however committed a few errors in his code. Rewrite the code after removing errors also underline the corrections made.

define reverse(num): 
    rev = 0 
    While num > 0: 
       rem == num %10 
       rev = rev*10 + rem 
       num = num/10 
    return rev 
print(reverse(1234))

Ans.:

def reverse(num): 
    rev = 0 
    while num > 0: 
       rem = num %10 
       rev = rev*10 + rem 
       num = num//10 
    return rev 
print(reverse(1234))

[4] Predict the output for following code:

def printMe(q,r=2):
  p=r+q**3
  print(p)
#main-code
a=10
b=5
printMe(a,b)
printMe(r=4,q=2)

Ans.:

a=10
b=5
printMe(10,5)

q=10
r=5
 p=r+q**3
  =5+10**3
  =5+1000
  =1005
printMe(4,2)

q=2
r=4
p=r+q**3
 =4+2**3
 =4+8
 =12
Output:
1005
12

[5] Predict the output of the following python code:

def foo(s1,s2):
   l1=[]
   l2=[]
   for x in s1:
     l1.append(x)
   for x in s2:
     l2.append(x)
   return l1,l2

a,b=foo("FUN",'DAY')
print(a,b)

Ans:

a,b=foo("FUN","DAY")

foo('FUN','DAY')
 l1=[]
 l2=[]
 for x in 'FUN':
     l1.append(x)
 So l1=['F','U','N']
 for x im 'DAY':
     l2.append(x)
So l2=['D','A','Y']

The output is:
['F','U','N']['D','A','Y']

[6] Preety has written a code to add two numbers . Her code is having errors. Rewrite the correct code and underline the corrections made.

def sum(arg1,arg2):
  total=arg1+arg2;
  print(”Total:”,total)
return total;

sum(10,20)
print(”Total:”,total)

Ans.:

def sum(arg1,arg2):
  total=arg1+arg2 #Semicolon not required
  print(”Total:”,total)
  return total #Any one statement is enough either return or print

total=sum(10,20)#total variable needs to be call a function
print(”Total:”,total)

[7] What do you understand the default argument in function? Which function parameter must be given default argument if it is used? Give example of function header to illustrate default argument.

Ans.:

The value provided in the formal arguments in the definition header of a function is called as default argument in function. 
They should always be from right side argument to the left in sequence. 
For example: 
def func( a, b=2, c=5): 
         # definition of function func( ) 
here b and c are default arguments

[8] Ravi a python programmer is working on a project, for some requirement, he has to define a function with name CalculateInterest(), he defined it as:

def CalculateInterest (Principal, Rate=.06,Time):
         # code

But this code is not working, Can you help Ravi to identify the error in the above function and what is the solution?

In the function CalculateInterest (Principal, Rate=.06,Time) parameters should be default parameters from right to left hence either Time should be provided with some default value or default value of Rate should be removed

[9] Rewrite the following code in python after removing all the syntax errors. Underline each correction done in the code.

Function F1():
  num1,num2 = 10
  While num1 % num2 = 0
     num1+=20
     num2+=30
  Else:      
    print('hello')

Ans.:

def F1():
  num1,num2 = 10, value is missing
  while num1 % num2 == 0:
     num1+=20
     num2+=30
  else:
    print('hello')

[10] Predict the output of the following code fragment:

def Change(P ,Q=30):
     P=P+Q
     Q=P-Q
     print(P,"#",Q)
     return(P)
R=150
S=100
R=Change(R,S)
print(R,"#",S)
S=Change(S)

Ans.:

R=150
S=100
R=change(150,100)
p=p+q
 =150+100
 =250
q=p-q
 =250-100
 =150

r=250
s=150

Print 1 - 250#150
Print 2 - 250#100

R=100
S=30
R=change(100,30)
p=p+q
 =100+30
 =130
q=p-q
 =130-30
 =150

Print 3 - 130#100

Answer:
250#150
250#100
130#100


130#100

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2 Marks important questions Python Functions Class 12

List and Functions 3 Marks important questions Computer Science Class 12

[1] Write a function ThreeLetters(L), where L is the list of elements (list of words) passed as an argument to the function. The function returns another list named ‘l3’ that stores all three letter words along with its index.

For example:

If L contains [“RAJ”, “ANKIT”, “YUG”, “SHAAN”, “HET”]

The list l3 will have [“RAJ”,0,”YUG”,2,”HET”,4]

Support your answer with a function call statement.

Ans.:

For answer click here…

[2] Write a function modifySal(lst) that accepts a list of numbers as an argument and increases the value of the elements (basic) by 3% if the elements are divisible by 10. The new basic must be integer values.

For example:

If list L contains [25000,15130,10135,12146,15030]

Then the modifySal(lst) should make the list L as [25750,15584,10135,12146,15030]

Write a proper call statement for the function.

Ans.:

def modifySal(lst):
    for i in range(len(lst)):
      if lst[i]%10==0:
        lst[i]=int(lst[i]+(lst[i]*0.03))
    return lst

basic_li=[25000,15130,10135,12146,15030]
print(modifySal(basic_li))

[3] Write a function not1digit(li), where li is the list of elements passed as an argument to the function. The function returns another list that stores the indices of all numbers except 1-digit elements of li.

For example:

If L contains [22,3,2,19,1,69]

The new list will have – [0,3,5]

Ans.:

def not1digit(li):
    l=[]  
    for i in range(len(li)):
      if li[i]>9:
        l.append(li[i])
    return l

li=[22,3,2,19,1,69]
print(not1digit(li))

[4] Write a function shiftLeft(li, n) in Python, which accepts a list li of numbers, and n is a numeric value by which all elements of the list are shifted to the left.

Sample input data of the list

Numlist= [23, 28, 31, 85, 69, 60, 71], n=3

Output Numlist-[85, 69, 60, 71, 23, 28, 31]

def LeftShift(li,n):
   li[:]=li[n:]+li[:n]
   return li
aList=[23, 28, 31, 85, 69, 60, 71]
n=int(input("Enter value to shift left:"))
print(LeftShift(aList,n))

[5] Write a function cube_list(lst), where lst is the list of elements passed as an argument to the function. The function returns another list named ‘cube_List’ that stores the cubes of all Non-Zero Elements of lst.

For example:

If L contains [2,3,0,5,0,4,0]

The SList will have – [8,27,125,64]

def cube_list(lst):
  cube_list=[]
  for i in range(len(lst)):
    if lst[i]!=0:
      cube_list.append(lst[i]**3)
  return cube_list
      
l=[2,3,0,5,0,4,0]
print(cube_list(l))

[6] Write a function in Python OddEvenTrans(li) to replace elements having even values with their 25% and elements having odd values with thrice (three times more) of their value in a list.

For example:

if the list contains [10,8,13,11,4] then

The rearranged list is as [2.5,2,39,33,1]

Ans.:

def OddEvenTrans(li):
  for i in range(len(li)):
    if l[i]%2==0:
      l[i]=l[i]*0.25
    else:
      l[i]=l[i]*3
  return li
l=[10,8,13,11,4]
print(OddEvenTrans(l))

[7] Write a function listReverse(L), where L is a list of integers. The function should reverse the contents of the list without slicing the list and without using any second list.

Example:

If the list initially contains [79,56,23,28,98,99]

then after reversal the list should contain [99,98,28,23,56,79]

Ans.:

def reverseList(li):
  rev_li=[]
  for i in range(-1,-len(li)-1,-1):
    rev_li.append(li[i])
  return rev_li
l=[79,56,23,28,98,99]
print(reverseList(l))

[8] Write a function in python named Swap50_50(lst), which accepts a list of numbers and swaps the elements of 1st Half of the list with the 2nd Half of the list, ONLY if the sum of 1st Half is greater than 2nd Half of the list.

Sample Input Data of the list:

l= [8, 9, 7,1,2,3]

Output = [1,2,3,8,9,7]

ddef Swap50_50(lst):
  s1=s2=0
  L=len(lst)
  for i in range(0,L//2):
    s1+=lst[i]
  for i in range(L//2, L):
    s2+=lst[i]
  if s1>s2:
    for i in range(0,L//2):
      lst[i],lst[i+L//2]=lst[i+L//2],lst[i]
l=[8,9,7,1,2,3]
print("List before Swap:",l)
Swap50_50(l)
print("List after swap:",l)

[9] Write a function vowel_Index(S), where S is a string. The function returns a list named ‘il’ that stores the indices of all vowels of S.

For example: If S is “TutorialAICISP”, then index List should be [1,4,6]

def vowel_Index(S):
  il=[]
  for i in range(len(S)):
    if S[i] in 'aeiouAEIOU':
      il.append(i)
  return il
s='TutorialAICSIP'
print(vowel_Index(s))

[10] Write a function NEW_LIST(L), where L is the list of numbers integers and float together. Now separate integer numbers into another list int_li.
For example:
If L contains [123,34.8, 54.5,0,8.75,19,86.12,56,78,6.6]
The NewList will have [123,0,19,56,78]

def NEW_LIST(L):
  int_li=[]
  for i in range(len(L)):
    if type(L[i])==int:
      int_li.append(L[i])
  return int_li
l=[123,34.8, 54.5,0,8.75,19,86.12,56,78,6.6]
print(NEW_LIST(l))

Important Questions File Handling Computer Science Class 12

In this section of Most expected questions Computer Science we are going to cover the most important questions from File handling concepts for Computer Science Class 12. Here we go!

File handling MCQs/1M questions

Follow the given link for 1 marks questions of file handling computer science class 12.

Topic	Article
40+ questions based on text file	Explore Now
25+ questions based on binary file	Explore Now
40+ questions based on CSV file	Explore Now
Previous year Board questions	Watch Now Video 1 | Video 2

File handling 2/3 marks questions

[1] A pre-existing text file info.txt has some text written in it. Write a python function countvowel() that reads the contents of the file and counts the occurrence of vowels(A,E,I,O,U) in the file.

Ans.:

def countVowel(): 
  c=0 
  f=open('info.txt') 
  dt=f.read() 
  for ch in data: 
      if ch.lower() in 'aeiou': 
                     c=c+1 
  print('Total number of vowels are : ', c)

[2] A pre-existing text file data.txt has some words written in it. Write a python function displaywords() that will print all the words that are having length greater than 3.

Example:

For the fie content:

A man always wants to strive higher in his life

He wants to be perfect.

The output after executing displayword() will be:

Always wants strive higher life wants perfect

Ans.:

def displaywords():
   f= open('data.txt','r')
   s= f.read()
   lst = s.split()
   for x in lst:
     if len(x)>3:
       print(x, end=" ")
   f.close()

[3] Write a function countINDIA() which read a text file ‘myfile.txt’ and print the frequency of word ‘India’ in each line. (Ignore its case)

Example:

If file content is as follows:

INDIA is my country.

I live in India, India is best.

India has many states.

The function should return :

Frequency of India in Line 1 is: 1

Frequency of India in Line 2 is: 2

Frequency of India in Line 3 is: 1

Ans.:

def countINDIA():
  f=open("myfile.txt")
  lines=f.readlines()
  for line in range(len(lines)):
    c=0
    w=lines[line].split()
    for i in w:
      if i.lower()=='india':
        c+=1
    print("Frequency of India in Line ",line+1," is:",c)
countINDIA()

[4] Write a function COUNT_AND( ) in Python to read the text file “STORY.TXT” and count the number of times “AND” occurs in the file. (include AND/and/And in the counting)

Ans.:

def COUNT_AND( ): 
    c=0 
    f=open(‘STORY.TXT','r') 
    dt = f.read() 
    w = dt.split() 
    for i in w: 
      if i.lower()=='and': 
             c=c+1 
    print("Word found ", c , " times")
    f.close()

[5] Write a function DISPLAYWORDS( ) in python to display the count of words starting with “t” or “T” in a text file ‘STORY.TXT’.

def DISPLAYWORDS( ):
    c=0
    f=open('STORY.TXT','r')
    l = f.read()
    w = l.split()
    for i in w:
        if i[0]=="T" or i[0]=="t":
            c=c+1
    f.close()
    print("Words starting with t are:",c)

Data File Handling 4 Marks Questions

[1] Priya of class 12 is writing a program to create a CSV file “clients.csv”. She has written the following code to read the content of file clients.csv and display the clients’ record whose name begins with “A‟ and also count as well as show no. of clients with the first letter “A‟ out of total records. As a programmer, help her to successfully execute the given task.
Consider the following CSV file (clients.csv):

1	Aditya	2021
2	Arjun	2018
3	Aryan	2016
4	Sagar	2022

Code:

import _____                                    # Line-1
def client_names():
  with open(______) as csvfile:                 # Line-2
    myreader = csv.___ (csvfile, delimiter=",") # Line-3
    count_rec=0
    count_s=0
    for row in myreader:
      if row[1][0].lower() == "s":
         print(row[0],",",row[1],",",row[2])
         count_s += 1
         count_rec += 1
 print(count_rec, count_s)

Read the questions given below and fill in the gaps accordingly: 1 + 1 + 2

1. State the module name required to be written in Line-1.
2. Mention the name of the mode in which she should open a file.
3. Fill in the gaps for given statements – Line-2 and Line-3.

[2] Arpan is a Python programmer. He has written code and created a binary file school.dat with rollno, name, class, and marks. The file contains few records. He now has to search records based on rollno in the file school.dat. As a Python expert, help him to complete the following code based on
the requirement given above:

Code:

import _______                    #Statement 1
def find_records():
   r=int(input('Enter roll no of student to be searched'))
   f=open(______________________) # staement2
   found=False
   try:
     while True:
        data=_______________     # statement 3
           for rec in data:
              if r==_______:     # staement4
                  found=True
                  print('Name: ',rec[1])
                  print('Class : ',rec[2])
                  print('Marks :',rec[3])
                  break
  except Exception:
      f.close()
  if found==True:
      print('Search successful')
  else:
      print('Record not exist')

Help Arpan to answer the following questions to fill in the given gaps: 1 + 1 + 2

1. Which module should be imported into the program? (Statement1)
2. Write the correct statement required to open a file school.dat in the required mode (Statement 2)
3. Which statement should Arpan fill in Statement 3 for reading data from the binary file school.dat? Also, Write the correct comparison to check the existence of the record (Statement 4).

[3] Arjun is a programmer, who has recently been given a task to write a python code to perform the following binary file operations with the help of two user-defined functions/modules:

1. GetPatients() to create a binary file called PATIENT.DAT containing student information – case number, name, and charges of each patient.
2. FindPatients() to display the name and charges of those patients who have charges greater than 8000. In case there is no patient having charges > 8000 the function displays an appropriate message. The function should also display the average charges also.

Ans.:

import pickle
def GetPatient():
  f=open("patient.dat","wb")
  while True:
    case_no = int(input("Case No.:"))
    pname = input("Name : ")
    charges = float(input("Charges :"))
    l = [case_no, pname, charges]
    pickle.dump(l,f)
    Choice = input("enter more (y/n): ")
    if Choice in "nN":
      break
      f.close()
def FindPatient():
  total=0
  cr=0
  more_8k=0
  
  with open("patient.dat","rb") as F:
    while True:
      try:
        R=pickle.load(F)
        cr+=1
        total+=R[2]
        if R[2] > 8000:
          print(R[1], " has charges =",R[2])
          more_8k+=1
      except:
        break
  try:
    print("average percent of class = ",total/more_8k)
  except ZeroDivisionError:
    print("No patient found with amount more than 8000")
  
GetPatient()
FindPatient()

[4] Mitul is a Python programmer. He has written a code and created a binary file emprecords.dat with employeeid, name, and salary. The file contains 5 records.

1. He now has to update a record based on the employee id entered by the user and update the salary. The updated record is then to be written in the file temp.dat.
2. The records which are not to be updated also have to be written to the file temp.dat.
3. If the employee id is not found, an appropriate message should to be displayed.

As a Python expert, help him to complete the following code based on the requirement given above:

import_______                #Statement 1
def update_data():
  rec={}
  fin=open("emprecords.dat","rb")
  fout=open("_____________") #Statement2
  found=False
  eid=int(input("Enter employee id to update salary::"))
  while True:
    try:
      rec=______________#Statement 3
      if rec["Employee id"]==eid:
        found=True
        rec["Salary"]=int(input("Enter new salary:: "))
        pickle.____________ #Statement 4
      else:
        pickle.dump(rec,fout)
    except:
     break
   if found==True:
     print("The salary of employee id",eid,"has been updated.")
  else: 
     print("No employee with such id is found")
  fin.close()
  fout.close()

Write answers for the following: (1 + 1 + 2)

1. Which module should be imported in the program? (Statement 1)
2. Write the correct statement required to open a temporary file named temp.dat. (Statement2)
3. Which statement should Mitul fill in Statement 3 to read the data from the binary file, emprecords.dat, and in Statement 4 to write the updated data in the file, temp.dat?

[5] Nandini has written a program to read and write using a csv file. She has written the following code but is not able to complete code.

import ___________                    #Statement 1
tr = ['BookID','Title','Publisher']
dt = [['1', 'Computer Science','NCERT'],['2','Informatics Practices','NCERT'],['3','Artificial Intelligence','CBSE']]
f = open('books.csv','w', newline="")
csvwriter = csv.writer(f)
csvwriter.writerow(tr)
_______________              #Statement 2
f.close()
f = open('books.csv','r')
csvreader = csv.reader(f)
top_row = _______________    #Statement 3
print(top_row)
for i in _________:          #Statement 4
  if i[2]=='NCERT':
      print(x)

Help her to complete the program by writing the missing lines by following the questions:

a) Statement 1 – Write the python statement that will allow Nandini to work with csv file.
b) Statement 2 – Write a python statement that will write the list containing the data available as a nested list in the csv file
c) Statement 3 – Write a python statement to read the header row into the top_row object.
d) Statement 4 – Write the object that contains the data that has been read from the file.

In the next section of Most expected questions in Computer Science class 12, we are going to cover questions from data file handling which can be asked in 5 marks. Let us begin!

Data File Handling 5 Marks Questions

[1] What is the advantage of using a csv file for permanent storage? Write a Program in Python that defines and calls the following user defined functions:

(i) insert() – To accept and add data of a apps to a CSV file ‘apps.csv’. Each record consists of a list with field elements as app_id, name and mobile to store id, app name and number of downloads respectively.

(ii) no_of_records() – To count the number of records present in the CSV file named ‘apps.csv’.

Ans.:

Advantages of a csv file:

• It is human readable – can be opened in Excel and Notepad applications
• It is just like text file
• It is common structure file can be opened by notepad, spreadsheet software like MS Excel and MS word also
• Easy to process data in tabular form

(i) Code for Function insert():

import csv
def insert():
  f=open('apps.csv','a',newline='')
  app_id=int(input("Enter App ID:"))
  app_name=input("Enter Name of App:")
  model=input("Enter Model:")
  company=input("Enter Company:")
  downloads=int(input("Enter no. downloads in thousands:"))
  l=[app_id,app_name,model,company,downloads]
  wo=csv.writer(f)
  wo.writerow(l)
  f.close()

(ii) Code for no_of_records()

Method 1

def no_of_records():
  f=open("apps.csv",'r')
  ro=csv.reader(f)
  l=list(ro)
  print("No. of records:",len(l))
  f.close()

Method 2

def no_of_records():
  f=open("apps.csv",'r')
  ro=csv.reader(f)
  c=0
  for i in ro:
    c+=1
  print("No. of records:",c)
  f.close()

Function Calling:

insert()
no_of_records()

[2] Give any one point of difference between a binary file and a csv file. Write a Program in Python that defines and calls the following user defined functions:

(i) add() – To accept and add data of an employee to a CSV file ‘emp.csv’. Each record consists of a list with field elements as eid, name and salary to store employee id, employee name and employee salary respectively.

(ii) search()- To display the records of the employee whose salary is more than 40000.

Ans.:

Binary File	CSV File
The binary file contains data in 0s and 1s form	CSV file contains data in tabular form
It is saved by .bin or .dat extension	It is saved by .csv extension
It must be created by a python program only	It can be created by notepad or spreadsheet
It is not a humanly readable file	It is a humanly readable file

Code for function add():

def add():
  f=open('emp.csv','a',newline='')
  empid=int(input("Enter employee ID:"))
  empname=input("Enter Employee Name:")
  sal=float(input("Enter Salary:"))
  l=[empid,empname,sal]
  wo=csv.writer(f)
  wo.writerow(l)
  f.close()

Code for function search()

def search():
  f=open("emp.csv",'r')
  ro=csv.reader(f)
  for i in ro:
    if float(i[2])>40000:
      print(i)
  f.close()

Function Calling:

add()
search()

[3] What is delimiter in CSV file? Write a program in python that defines and calls the following user defined function:

i) Add() – To accept data and add data of employee to a CSV file ‘record.csv’. Each record consists of a list with field elements as empid, name and mobile to store employee id, employee name and employee salary.

ii) CountR():To count number of records present in CSV file named ‘record.csv’.

Ans.:

Delimiter refers to a character used to separate the values or lines in CSV file. By default delimiter for CSV file values is a comma and the new line is ‘\n’. Users can change it anytime.

Code is similar as question 1, do yourself.

[4] Give any one point of difference between a text file and csv file. Write a python program which defines and calls the following functions:

i) add() – To accept and add data of a furniture to a csv file ‘furdata.csv’. Each record consists of a list with field elements such as fid, name and fprice to store furniture id, furniture name and furniture price respectively.

ii) search() – To display records of sofa whose price is more than 12000.

Ans.:

Text File	CSV File
It represents data into ASCII format.	It represents data into ASCII form and in tabular form.

Code for add():

def add():
  f=open('furdata.csv','a',newline='')
  fid=int(input("Enter furniture ID:"))
  fname=input("Enter furniture Name:")
  price=float(input("Enter price:"))
  l=[fid,fname,price]
  wo=csv.writer(f)
  wo.writerow(l)
  f.close()

Code for search()

def search():
  f=open("furdata.csv",'r')
  ro=csv.reader(f)
  for i in ro:
    if i[1].lower()=='sofa' and float(i[2])>12000:
      print(i)
  f.close()

[5] Archi of class 12 is writing a program to create a CSV file “user.csv” which contains user name and password for some entries. He has written the following code. As a programmer, help her to successfully execute the given task.

import ___________ #Line1
def addCsvFile(user, pwd):
  f=open('user.csv','_') #Line2
  w=csv.writer(f)
  w.writerow([UserName,Password])
  f.close( )

csv file reading code
def readCsvFile(): #to read data from CSV file
  with open('user.csv','r') as f:
     ro=csv.________________(newFile) #Line3 
     for i in ro: 
         print(i) 
  f.__________ #Line4
addCsvFile('Aditya','987@555')
addCsvFile('Archi','arc@maj')
addCsvFile('Krish','krisha@Patel')
readCsvFile()
OUTPUT___________________ #Line 5

1. What module should be imported in #Line1 for successful execution of the program?
2. In which mode file should be opened to work with user.csv file in#Line2
3. Fill in the blank in #Line3 to read data from csv file
4. Fill in the blank in #Line4 to close the file
5. Write the output he will obtain while executing Line5

Ans.:

1. csv
2. ‘a’
3. reader
4. close
5. Output:

['Aditya'.'987@555']
['Archi','arc@maj']
['Krish','Krisha@Patel']

Watch video for more understanding:

5 Marks most important questions File Handling Class 12

Data Structure Stack questions

The first topic we are going to cover is Data Structure Stack. Here we go!

1 mark objective types questions data structure stack class 12 computer science

[1] Kunj wants to remove an element from empty stack. Which of the following term is related to this?

a) Empty Stack

b) Overflow

c) Underflow

d) Clear Stack

[2] ____________ is an effective and reliable way to represent, store, organize and manage data in systematic way.

[3] Which of the following is elementary representation of data in computers?

a) Information

b) Data

c) Data Structure

d) Abstract Data

[4] ____________ represents single unit of certain type.

a) Data item

b) Data Structure

c) Raw Data

d) None of these

[5] Statement A: Data Type defines a set of values alog with well-defined operations starting its input-output behavior

Statement B: Data Structure is a physical implementation that clearly defines a way of storing, accessing, manipulating data.

a) Only Statement A is True

b) Only Statement B is True

c) Both are True

d) Both are False

[6] Which of the following python built in type is mostly suitable to implement stack?

a) dictionary

b) set

c) tuple

d) list

[7] The Data Structures can be classified into which of the following two types?

a) Stack and Queue

b) List and Dictionary

c) Simple and Compund Data Structure

d) Easy and Comoplex Data Structure

[8] Identify Data Structure from the given facts:

1. I am single level data strcuture.
2. My elements are formed from a sequence.

a) Linear Data Structure

b) Non-Linear Data Structure

c) Dynamic Data Structure

d) Static Data Structure

[9] Which of the following is an example of non-linear data structure?

a) Stack

b) Queue

c) Linked List

d) Tree

[10] Which of the following is/are an example(s) of python ‘s built-in linear data structure?

a) List

b) Tuple

c) Set

d) All of these

[11] _____________ is a linear data structure implemented in LIFO manner where insertion and deletion are restricted to one end only.

a) Stack

b) Queue

c) Tree

d) Linked List

[12] Which of the following is an example of stack?

a) Students standing in Assembly

b) People standing railway ticket window

c) Chairs arranged in a vertical pile

d) Cars standing on the road on traffic signal

[13] Which of the following operation of stack is performed while inserting an element into the stack?

a) push

b) pop

c) peep

d) Overflow

[14] Which of the folloiwng operation is considered as deletion of element from stack?

a) push

b) pop

c) underflow

d) overflow

[15] Which of the following pointer is very essential in stack operations?

a) front

b) top

c) middle

d) bottom

[16] The fixed length data structure is known as _____________

a) dynamic data stcuture

b) fixed length data structure

c) static data stucture

d) intact data structure

[17] __________ refers to insepecting an element of stack without removing it.

a) push

b) pop

c) peek

d) underflow

[18] Consider the following data:

[11,20,45,67,23]

The following operations performed on these:

push(19)

pop()

push(24)

pus(42)

pop()

push(3)

What will be the contents of the list evelntually?

a) [11,20,45,67,23]

b) [3,24,11,20,67,23]

c) [42,24,11,20,67,23]

d) [24,11,20,67,23]

[19] The LIFO structure can be also same as ______________

a) FILO

b) FIFO

c) FOFI

d) LOFI

[20] Consider the folloiwing data structure implemented a list as stack:

11

22

23

34

91

Which of the following is function is executed thrice to get this result:

34

91

a) delete()

b) pop()

c) remove()

d) clear()

Most expected 2 marks questions Stack Computer Science Class 12

[1] What is Stack? Write any one application of Stack?

[2] List out any two real-life examples of Stack.

[3] Define stack. What is the significance of TOP in stack?

[4] Give any two characteristics of stacks.

[5] What do you mean by push and pop operations on stack?

[6] What is LIFO data structure? Give any two applications of a stack?

[7] Name any two linear Data Structures? What do you understand by the term LIFO?

[8] Name four basic operations performed on stack.

[9] Why stack is called LIFO data structure?

[10] What do you mean by underflow in the context of stack?

[11] Consider STACK=[23,45,67,89,51]. Write the STACK content after each operations:

1. STACK.pop( )
2. STACK.append(99)
3. STACK.append(87)
4. STACK.pop( )

[12] Differentiate between list and stack.

[13] Differentiate between push and pop in stacks.

[14] Write an algorithm for pop operation in stack.

[15] Write an algorithm for push operation in stack.

Watch this video for more understanding:

If you are looking for notes on stack data structure, click on this link:

Data Structure Stack Class 12

Follow this link for more questions:

QnA Data Structure Class 12

Most expected 3 marks Stack Programming questions computer science

1. Write a function push (student) and pop (student) to add a new student name and remove a student name from a list student, considering them to act as PUSH and POP operations of stack Data Structure in Python.

Ans.:

def push(student):
    name=input("Enter student name:")
    student.append(name)

def pop(student):
   if student==[]:
        print("Underflow")
   else:
        student.pop()

2. Write PUSH(Names) and POP(Names) methods in python to add Names and Remove names considering them to act as Push and Pop operations of Stack.

def PUSH(Names):
   name=input("Enter name:")
   Names.append(name)

def POP(Names):
    if Names==[]:
      print("Underflow")
    else:
       Names.pop()

3. Ram has created a dictionary containing names and age as key value pairs of 5 students. Write a program, with separate user defined functions to perform the following operations:

Push the keys (name of the student) of the dictionary into a stack, where the corresponding value(age) is lesser than 40. Pop and display the content of the stack.

For example:  If the sample content of the dictionary is as follows:

R={“OM”:35,”JAI”:40,”BOB”:53,”ALI”:66,”ANU”:19}  

The output from the program should be:

ANU OM

R={"OM":35,"JAI":40,"BOB":53,"ALI":66,"ANU":19}

def Push(stk,n):
   stk.append(n)

def Pop(stk):
   if stk!=[]:
     return stk.pop()
   else:
     return None
s=[]
for i in R:
   if R[i]<40:
      Push(s,i)

while True:
    if s!=[]:
       print(Pop(s),end=" ")
    else:
       break

4. SHEELA has a list containing 5 integers. You need to help Her create a program with separate user defined functions to perform the following operations based on this list.

1. Traverse the content of the list and push the odd numbers into a stack.
2. Pop and display the content of the stack.

For Example:

If the sample Content of the list is as follows:

N=[79,98,22,35,38]

Sample Output of the code should be:

35,79

N=[79,98,22,35,38]

def Push(stk,on):
   stk.append(on)

def Pop(stk):
   if stk==[]:
     return None
   else:
     return stk.pop()
stk=[]

for i in N:
   if i%2!=0:
      Push(stk,i)

while True: 
    if stk!=[]:
      print(Pop(stk),end=" ")
    else:
      break

5. Write a function in Python PUSH_IN(L), where L is a list of numbers. From this list, push all even numbers into a stack which is implemented by using another list.

N=[79,98,22,35,38]

def Push(stk,on):
   stk.append(on)

def Pop(stk):
   if stk==[]:
     return None
   else:
     return stk.pop()
stk=[]

for i in N:
   if i%2==0:
      Push(stk,i)

while True: 
    if stk!=[]:
      print(Pop(stk),end=" ")
    else:
      break

6. Write a function in Python POP_OUT(Stk), where Stk is a stack implemented by a list of numbers. The function returns the value which is deleted/popped from the stack.

def POP_OUT(Stk):
   if Stk==[]:
      return None
   else:
      return Stk.pop()

7. Julie has created a dictionary containing names and marks as key value pairs of 6 students. Write a program, with separate user defined functions to perform the following operations:

1. Push the keys (name of the student) of the dictionary into a stack, where the corresponding value (marks) is greater than 75.
2. Pop and display the content of the stack.

For example:

If the sample content of the dictionary is as follows:

R={“OM”:76, “JAI”:45, “BOB”:89, “ALI”:65, “ANU”:90, “TOM”:82}

The output from the program should be: TOM ANU BOB OM

R={"OM":76, "JAI":45, "BOB":89, "ALI":65, "ANU":90, "TOM":82}
def Push(stk,n):
   stk.append(n)

def Pop(stk):
   if stk!=[]:
     return stk.pop()
   else:
     return None
s=[]
for i in R:
   if R[i]>75:
      Push(s,i)

while True:
    if s!=[]:
       print(Pop(s),end=" ")
    else:
       break

8. Raju has created a dictionary containing employee names and their salaries as key value pairs of 6 employees. Write a program, with separate user defined functions to perform the following operations:

1. Push the keys (employee name) of the dictionary into a stack, where the corresponding value (salary) is less than 85000.
2. Pop and display the content of the stack.

For example:

If the sample content of the dictionary is as follows:

Emp={“Ajay”:76000, “Jyothi”:150000, “David”:89000, “Remya”:65000, “Karthika”:90000, “Vijay”:82000}

The output from the program should be:

Vijay Remya Ajay

Emp={"Ajay":76000, "Jyothi":150000, "David":89000, "Remya":65000, "Karthika":90000, "Vijay":82000}

def Push(stk,sal):
    stk.append(sal)

def Pop(stk):
  if stk==[]:
    return None
  else:
    return stk.pop()

stk=[]

for i in Emp:
   if Emp[i]<85000:
     Push(stk,i)

while True:
  if stk!=[]:
    print(Pop(),end=" ")
  else:
    break 

9. Anjali has a list containing temperatures of 10 cities. You need to help her create a program with separate user-defined functions to perform the following operations based on this list.

1. Traverse the content of the list and push the negative temperatures into a stack.
2. Pop and display the content of the stack.

For Example:  

If the sample Content of the list is as follows:

T=[-9, 3, 31, -6, 12, 19, -2, 15, -5, 38]

Sample Output of the code should be: -5 -2 -6 -9

T= [-9, 3, 31, -6, 12, 19, -2, 15, -5, 38]

def Push(s,n):
  s.append(n)

def Pop(s):
  if s!=[]:
   return s.pop()
  else:
   return None


s=[]
for i in T:
   if i<0:
     Push(s,i)

while True:
  if s!=[]:
   print(Pop(s),end = " ")
  else:
   break

10. Ms.Suman has a list of integers. Help her to create separate user defined functions to perform following operations on the list.

1. DoPush(elt) to insert only prime numbers onto the stack.
2. DoPop() to pop and display content of the stack.

For eg:if L=[2.5,6,11,18,24,32,37,42,47] then stack content will be 2 5 11 37 47

def DoPush(elt):
 L= [2,5,6,11,18,24,32,37,42,47]
 for i in L:
  for j in range(2,i):
    if i % j ==0:
     break
  else:
    elt.append(i)


def DoPop(s):
  if s!=[]:
     return s.pop()
  else:
     return None

s=[]
DoPush(s)

while True:
  if s!=[]:
    print(DoPop(s),end=" ")
  else:
    break

11. Mr. Ramesh has created a dictionary containing Student IDs and Marks as key value pairs of students. Write a program to perform the following operations Using separate user defined functions.

1. Push the keys (IDs) of the dictionary into the stack, if the corresponding marks is >50
2. Pop and display the content of the stack

For eg:if D={2000:58,2001:45,2002:55,2003:40} Then output will be: 2000,2002

Do Yourself…

12. Write AddNew (Book) and Remove(Book) methods in Python to add a new Book and Remove a Book from a List of Books Considering them to act as PUSH and POP operations of the data structure Stack?

def AddNew(Book):
   name=input("Enter Name of Book:")
   Book.append(name)

def Remove(Book):
   if Book==[]:
    print("Underflow")
   else:
    Book.pop()

13. Assume a dictionary names RO having Regional Offices and Number of nodal centre schools as key-value pairs. Write a program with separate user-defined functions to perform the following operations:

1. Push the keys (Name of Region Office) of the dictionary into a stack, where the corresponding value (Number of Nodal Centre Schools) is more than 100.
2. Pop and display the content of the stack.

For example

If the sample content of the dictionary is as follows:

RO={“AJMER”:185, “Panchkula”:95, “Delhi”:207, “Guwahati”:87, “Bubaneshwar”:189}

The output from the program should be:

AJMER    DELHI  BHUBANESHWAR

Do yourself…

14. Write a function in Python PUSH (Lst), where Lst is a list of numbers. From this list push all numbers not divisible by 7 into a stack implemented by using a list. Display the stack if it has at least one element, otherwise display appropriate error message.

def PUSH(Lst):
  stk=[]
  for i in range(len(Lst)):
    if Lst[i]%7==0:
      stk.append(Lst[i])

  if len(stk)==0:
    print("Stack is underflow")
  else:
    print(stk)

15. Write a function in Python POP(Lst), where Lst is a stack implemented by a list of numbers. The function returns the value deleted from the stack.

def POP(Lst):
   if len(stk)==0:
    return None
   else:
    return Lst.pop()

16. Reva has created a dictionary containing Product names and prices as key value pairs of 4 products. Write a user defined function for the following:

PRODPUSH()  which takes a list as stack and the above dictionary as the parameters. Push the keys (Pname of the product) of the dictionary into a stack, where the corresponding price of the products is less than 6000. Also write the statement to call the above function. 

For example: If Reva has created the dictionary is as follows: 

Product={“TV”:10000, “MOBILE”:4500, “PC”:12500, “FURNITURE”:5500}

The output from the program should be: [ ‘FURNITURE’, ‘MOBILE’]

Do Yourself…

17. Pankaj has to create a record of books containing BookNo, BookName and BookPrice. Write a user- defined function to create a stack and perform the following operations:   

1. Input the Book No, BookName and BookPrice from the user and Push into the stack.
2. Display the status of stack after each insertion.

def Push():
   books=[]
   stk=[]
   bno=int(input("Enter Book Number:"))
   bname=input("Enter Book Name:")
   bprice=input("Enter Book Price:")
   books=[bno,bname,bprice]
   stk.append(books)
   print(stk)   

18. Write a function in Python PUSH(mydict),where mydict is a dictionary of phonebook(name and mobile numbers), from this dictionary push only phone numbers having last digit is greater than or equal to 5 to a stack implemented by using list. Write function POP() to pop and DISPLAY() to display the contents.

if it has at least one element, otherwise display “stack empty” message.

>>> mydict={9446789123:”Ram”,8889912345:”Sam”,7789012367:”Sree”}

>>> push(mydict)

Phone number: 9446789123 last digit is less than five which can’t be pushed

Stack elements after push operation : [7789012367, 8889912345]

mydict={9446789123:"Ram",8889912345:"Sam",7789012367:"Sree"}

def Push(mydict):
    stk=[]
    for i in mydict:
        if i%10>=5:
            stk.append(i)
    print(stk)

Push(mydict)

19. Write a function to push an element in a stack which adds the name of passengers on a train, which starts with capital ‘S’. Display the list of passengers using stack.

For example: L = [‘Satish’,’Manish’,’Sagar’,’Vipul’]

Output will be: Satish Sagar

L = ['Satish','Manish','Sagar','Vipul']
def Push(L,name):
    L.append(name)
stk=[]

for i in L:
    if i[0]=='S':
        Push(stk,i)

print(stk)

20. In a school a sports club maintains a list of its activities. When a new activity is added details are entered in a dictionary and a list implemented as a stack. Write a push() and pop() function that adds and removes the record of activity. Ask user to entre details like Activity, Type of activity, no. of players required and charges for the same.

Do Yourself…

Watch this video for practical understanding.

In the next section of Most expected questions Computer Science, I am going to discuss questions from unit 2 computer networks.

Most expected questions Unit II Computer Networks Computer Science Class 12

So let us discuss the most expected questions from Unit II Computer Networks for Computer Science Class 12. From this unit 1, 2, 3, 4, and 5 marks are going to be asked in your board exams. So here we go!

1 mark Unit 2 Computer Networks most expected questions computer science class 12

1. ……………………………. is a network of physical objects embedded with electronics, software, sensors and network connectivity.
2. ……………….. is a device that forwards data packets along networks.
3. ———————- describes the maximum data transfer rate of a network or Internet connection.
4. It is an internet service for sending written messages electronically from one computer to another. Write the service name.
5. As a citizen of india , What advise you should give to others for e-waste disposal?
6. Name the protocol that is used to send emails.
7. Your friend Ranjana complaints that somebody has created a fake profile on Facebook and defaming her character with abusive comments and pictures. Identify the type of cybercrime for these situations.
8. Name The transmission media best suitable for connecting to hilly areas.
9. Write the expanded form of Wi-Fi.
10. Rearrange the following terms in increasing order of data transfer rates. Gbps, Mbps, Tbps, Kbps, bps
11.   ______is a communication methodology designed to deliver both voice and multimedia communications over Internet protocol. 
12. Out of the following, which is the fastest wired and wireless medium of transmission? Infrared, coaxial cable, optical fibre, microwave, Ethernet cable

Answers:

1. IoT
2. router
3. Network bandwidth
4. Email
5. People can take e-waste to recycling centres
6. SMTP
7. Cyber Stalking
8. Radiowave or Microwave
9. Wireless Fidelity
10. bps -> Kbps -> Mbps -> Gbps -> Tbps
11. VoIP
12. Wired – Optical Fibre, Wireless – Microwave

Most expected 2 mark questions Unit 2 Computer networks

[1] Mr. Pradeep is working as a network admin in Durga Pvt. Ltd. He needs to connect 40 stand-alone computers in one unit using a server. How it is beneficial for the company? List out any two points.

[2] Differentiate between LAN, MAN, WAN.

[3] Dhara wants to connect her telephone network with the internet. Suggest a device she should use for the same and write any two functions of the device.

[4] What is an IP address? Write one example of IP Address.

[5] Bharti wants to know the term used for the process of converting a domain name into IP address. How it works?

[6] Illustrate the layout for connecting 5 computers in a Bus and a Star topology of Networks.

[7]

(a) Santosh wants a client/server protocol, in which e-mail is received and held by him on his computer from an Internet server. Regularly, it should check his mailbox on the email server and download mails to his computer. Which protocol out of the following will be ideal for the same?

(i) POP3

(ii) SMTP

(iii) VoIP

(iv) HTTP

(b) Riya is in India and she is interested in communicating with her friend in Canada. She wants to show one of her paintings to him and also wants to explain how it was prepared without physically going to Canada. Which protocol out of the following will be ideal for the same?

(i) POP3          

(ii) SMTP               

(iii) VoIP                

(iv) HTTP

[8]

(a) Ketan is working as a team leader in Resonance LTD. Company. He wants to host an online meeting for all the branches of India and present an annual report. Which technology is best suited for such a task?

(b) Mahi is accessing remote computers and data over TCP/IP networks. Which protocol is used to do this?

[9] Write short note on packet switching, message switching and circuit switching.

[10] Out of the following wired and wireless mediums of communication, which is the fastest:

Infrared, Coaxial Cable, Ethernet Cable, Microwave, Optical Fiber

[11] Vidya College has three departments that are to be connected into a network.

(a) Which of the following communication medium out of the given options should be used by the college for connecting their departments for very effective high-speed communication?

1. Coaxial cable
2. Optical Fibre
3. Ethernet Cable

(b) Also name the type of network out of (LAN/WAN/MAN) formed between various departments of the college.

[12]

(a) Which network device regenerates the signal over the same network before the signal becomes too weak or corrupted .

(b) Which network device connects two different networks together that work upon different networking models so that two networks can communicate properly.

[13]

(a) Which of the following is/are not communication media?

(i) Microwaves

(ii) Optical Fiber cable

(iii) Node

(iv) Radio waves

(b) Which of the following is/are not a topology?

(i) Star

(ii) Bus

(iii) Ring

(iv) Ethernet

[14] Identify the following media out of guided and unguided media?

Ethernet, Infrared, Bluetooth, Fibre Optic, Coaxial, Satellite, Radiowave, Microwave

[15] Name the devices :

1. This device links two networks together and is not a broadcast device, as it filters traffic depending upon the receiver’s MAC address.
2. This device offers a dedicated bandwidth.

[16] Expand TCP/IP. Write the purpose of TCP/IP in the communication of data on a network.

[17] Write the expanded names for the following abbreviated terms used in Networking:

(i) MBPS                            

(ii) WAN                            

(iii) CDMA                                        

(iv) WLL

[18] Give two advantages and two disadvantages of tree topology.

[19] Define the following terms: website , web browser

[20] Expand the following: ARPANET, NSFNet

[21] Identify the transmission medium used in the following:

1. TV Remotes
2. Cellular Networks

[22] Define: Web Server, Web Hosting

[23] Differentiate between IP address and MAC address.

[24] (i) Name the connector used to connect ethernet cable to computer and hub or switch.

(ii) Name the cables used in TV networks.

[25] (i) Name a network topology, which is used to maximize speed and make each computer
independent of the network.
(ii) Suggest a switching technique in which the information is transferred using Store and
Forward mechanism.

[26] Write two advantages of using an optical Fiber cable over a Twisted Pair cable to connect two service stations which are 200m away from each other.

[27] What is the difference between hub and switch? Which is preferable in a large network of computers and why?

[28] Give two advantages and two disadvantages of Bus topology.

[29] Prakash wishes to install a wireless network in his office. Explain him the differences between guided and unguided media.

[30] Which media is best for the following:

(i) Hilly Area

(ii) Large Industries

(iii) Point to point communication between two individuals

(iv) 4G

Most expected 4 Marks questions Unit II Computer Networks Computer Science Class 12

Watch this video for 4 marks questions from Unit II Computer networks class 12 Computer Science.

Most expected questions Unit III Database Management Computer Science Class 12

In the next section of Most expected questions Computer Science Class 12 we are going to cover questions from Unit III Database Management System Computer Science Class 12. From this unit 1, 2, 3 and 4 marks will be asked. Here we go!

Most expected MCQ questions Unit III Database Management System Computer Science Class 12

[1] Vishal is giving an online test on the computer. The question he got on screen is which of the following is a valid SQL statement?

a) DELETE ALL ROWS FROM TABLE STUDENT;

b) DELETE * from student;

c) DROP all rows from student;

d) DELETE FROM student;

Select an appropriate option to help him.

[2] Yashvi wants to change the structure of table in MySQL. Select an appropriate SQL command and help her to accomplish her task.

a) update

b) alter

c) modify

d) change

[3] Alpesh wants to remove a column from a table in SQL. Which command is used to remove a column from a table in SQL?

a) update

b) remove

c) alter

d) drop

[4] Observe the given keywords used in mysql queries and identify which keyword is not used with DDL comamnd?

a) DROP

b) MODIFY

c) DISTINCT

d) ADD

[5] Bhavi wants to assign NULL as the value for all the tuples of a new Attribute in a relation. Select an appropriate command to fulfill her need.

a) MODIFY

b) DROP

c) ADD

d) ALTER

[6] Kiran wants to remove rows from a table. She has given the following commands but she is confused about which one is the correct command. Help her to identify the correct command to accomplish her task.

a) DELETE command

b) DROP Command

c) REMOVE Command

d) ALTER Command

[7] State true or false – “Drop command will remove the entire database from MySQL.”

[8] There are various keys associated with database relations. Select an appropriate invalid key out of the following:

a) Primary Key

b) Master key

c) Foreign Key

d) Unique Key

[9 ]Which of the following statements is True?

a) There can be only one Foreign Key in a table

b) There can be only one Unique key is a table

c) There can be only one Primary Key in a Table

d) A table must have a Primary Key

[10] Raj is preparing for DBA. He read something as a non-key attribute of a relation whose values are derived from the primary key of another table. Help him to identify the term he read about.

a) Primary key

b) Foreign key

c) candidate key

d) Alternate key

[12] Anirudh wants to use the SELECT statement combined with the clause which returns records without repetition. Help him by selecting appropriate keyword to fulfill his task.

a) distinct

b) describe

c) unique

d) null

[13] Vinay wants to identify the keyword used to obtain unique values in a SELECT query from the following

a) UNIQUE

b) DISTINCT

c) SET

d) HAVING

[14] Priyank wants to display total number of records from MySQL database table. Which command help him to the task out of the following?

a) total(*)

b) sum(*)

c) count(*)

d) all(*)

[15] Udit is learning the concept of operators in SQL. Help him to identify the Logical Operators used in SQL by selecting the appropriate option.

a) AND,OR,NOT

b) &&,||,!

c) $,|,!

d) None of these

Watch this video for more understanding:

15 MCQs DBMS and MySQL Computer Science Class 12

[16] Hriday wants to fetch records from a table that contains some null values. Which of the following ignores the NULL values in SQL?

a) Count(*)

b) count(column_name)

c) total(*)

d) None of these

Most expected 2/3 marks questions Unit III Database Management Computer Science Class 12

[1] What is MySQL? List some popular versions of MySQL.

[2] Hetal is inserting “Rathod” in the “LastName” column of the “Emp” table but an error is being displayed. Write the correct SQL statement.

INSERT INTO Emp(‘Rathod’)VALUES(LastName) ;

[3] Darsh created the following table with the name ‘Friends’ :

Table : Friends

Freind_Code	Name	Hobbies
F001	Anurag	Traveling
F002	Manish	Watching Movies

Now, Darsh wants to delete the ‘Hobbies’ column. Write the MySQL statement.

[4] Mr. Nikunj entered the following SQL statement to display all Salespersons of the cities “Chennai” and ‘Mumbai’ from the table ‘Sales’.

Table: Sales

Scode	Name	City
S0001	Krishanan Iyer	Chennai
S0002	Atmaram Bhide	Mumbai
S0003	Jethalal Gada	Bhachau
S0004	Venugopal Srinavasana	Chennai
S0005	Mandar Mumbaikar	Mumbai

SELECT * FROM Sales WHERE City=‘Chennai’ AND City=‘Mumbai’;

He is getting the Empty Set as output. Explain the problem with the statement and rewrite the correct statement.

[5] Is NULL value the same as 0 (zero) ? Write the reason for your answer.

[6] Write the UPDATE command to increase the commission (Column name : COMM) by 500 of all the Salesmen who have achieved Sales (Column name : SALES) more than 200000. The table’s name is COMPANY.

[7] While using SQL pattern matching, what is the difference between ‘_’ (underscore) and ‘%’ wildcard symbols?

[8] What is the meaning of open source and open source database management system?

[9] In a table employee, a  column occupation contains many duplicate values. Which keyword would you use if wish to list of only different values? Support your answer with example.

[10] How is alter table statement different from UPDATE statement?

[11] Charvi wants to delete the records where the first name is Rama in the emp table. She has entered the following SQL statement. An error is being displayed. Rewrite the correct statement.

Delete from firstname from emp;

[12] What is the relationship between SQL and MySQL?

[13] Rani wants to add another column ‘Hobbies’ with datatype and size as VARCHAR(50) in the already existing table ‘Student’. She has written the following statement. However, it has errors. Rewrite the correct statement.

MODIFY TABLE Student Hobbies VARCHAR;

[14] Write SQL query to display employee details from table named ‘Employee’ whose ‘firstname’ ends with ‘n’ and firstname contains a total of 4 characters (including n).

[15] Identify aggregat functions of MySQL amongst the following :

TRIM(), MAX(), COUNT(*), ROUND()

[16] Write the following statement using ‘OR’ logical operator :

SELECT first_name, last_name, subject FROM studentdetails WHERE subject IN (‘Maths’, ‘Science’);

[17] What is MySQL used for? Ajay wants to start learning MySQL. From where can he obtain the MySQL software?

[18] In the table ‘‘Student’’, Priya wanted to increase the Marks (Column Name:Marks) of those students by 5 who have got Marks below 33. She has entered the following statement :

SELECT Marks+5 FROM Student WHERE Marks <33;

Rewrite the correct statement.

[19] Consider a table Accounts and answer the following:

(i) Name the Data type that should be used to store AccountCodes like ‘‘A1001’’ of Customers.

(ii) Name two Data types that require data to be enclosed in quotes.

[20] Given the table ‘Player’ with the following columns :

Table – Player

Pcode	Points
P001	95
P002	82
P003	74
P004	93
P005	77

Write the output of the following queries:

1. SELECT AVG(POINTS) FROM Player;
2. Select COUNT(POINTS) FROM Player;

Watch this video for more understanding:

[21] Differentiate between char and varchar. Priya has created a table and used char(10) and varchar(10) as a datatype for two of the columns of her table. What (10) indicate here?

[22] ‘Employee’ table has a column named ‘CITY’ that stores city in which each employee resides. Write SQL query to display details of all rows except those rows that have CITY as ‘DELHI’ or ‘MUMBAI’ or ‘CHANDIGARH’.

[23] Ajay has applied a Constraint on a column (field) such that

(i) Ajay will certainly have to insert a value in this field when he inserts a new row in the table.

(ii) If a column is left blank then it will accept 0 by itself.

Which constraints has Ajay used?

[24] ‘STUDENT’ table has a column named ‘REMARK’ that stores Remarks. The values stored in REMARK column in different rows are “PASS” or “NOT PASS” or “COMPTT” etc. Write SQL query to display details of all rows except those that have REMARK as “PASS”.

[25] Consider the table : Company

SID	Sales
S001	250
S002	100
S002	200

What output will be displayed by the following SQL statements?

(i) select avg(sales) from company where sales>200;

(ii) select sum(sales)/2 from company where SID=’S002′;

[26] Consider the table ‘Hotel’ given below:

Table : Hotel

EMPID	Category	Salary
1001	Permanent	25000
1002	Contract	18000
1003	Adhoc	10000
1004	Contract	12000
1005	Permanent	20000

Mr. Vinay wanted to display the average salary of each Category. He entered the following SQL statement. Identify error(s) and Rewrite the correct SQL statement.

SELECT Category, Salary FROM Hotel GROUP BY Category;

Write one more query to display maximum salary category wise.

[27] Namrata has created the following table with the name ‘Order’.

Field	Constraint
OrderID	Primary Key
OrderDate	Not Null
OrderAmount
StoreID

Answer the following:

1. What is the data type of columns OrderId and OrderDate in the table Order?
2. Namrata is now trying to insert the following row : O102, NULL, 59000, S105

[28] Write SQL query to create a table ‘Event’ with the following structure :

Field	Data Type	Size	Constraint
eventid	varchar	5	Primary Key
event	varchar	30	not null
location	varchar	50	Ahmedabad should be by default
clientid	integer		Foreign Key Parent table (Client)
eventdate	date

[29] How is a Primary key constraint different from a Unique key constraint?

[30] Write two similarities between CHAR and VARCHAR data types.

[31] Consider “TravelPackage” table with “source” column. Entering data for the Location column is optional. If one enters data for a row with no value for the “source” column, what value will be saved in the “source” column? Write SQL statement to display the details of rows in the “travelpackage” table whose location is left blank.

[32] Define: Field/Attribute, Tuple/Record

[33] Define: Degree and Cardinality

[34] Define: Candidate Key, Alternate Key

[35] A NULL value can be inserted into a foreign key? Justify your answer.

[36] Ravindra is confused about what is a domain? Clear his confusion with an example.

[37] Consider the following table – Student

AdmNo	RollNo	Name	Class	Marks
1001	1	Shailesh	X	76
1002	2	Kamalaa	XII	89
1003	3	Dinesh	XI	85

Identify the candidate keys and alternate keys.

[38] Enlist any four popular RBMDS software.

[39] A table “clustergames” exists with 4 columns and 6 rows. What is its degree and cardinality, initially? 2 rows are added to the table and 1 column deleted. What will be the degree and cardinality now?

[40] Sejal wants to create a table patient. Help her to do the following:

(i) She is confused about how the dates are stored in MySQL? Suggest the date format.

(ii) She want to display all records from the table and she wrote the following command:

show * from patient;

She is not getting the output. Rewrite the correct statement.

[41] What is sorting? Which keyword is used to sort data from the table in SQL?

[42] Rajni wants to apply sorting on a table through SQL. But he is not aware about how to use order by clause. Explain the order by clause in short to him with example.

[43] Consider the given table states and write the output of queries given below:

Code	Sname	Capital	Districts	Flower	FDate
I001	Gujarat	Gandhinagar	33	Marigold	1960-05-01
I002	Rajasthan	Jaipur	50	Rohida	1949-03-30
I003	Goa	Panaji	2	Jasmine	1987-05-30
I004	Punjab	Chandigarh	23	Gladiolus	1950-01-26
I005	Kerala	Thiruvananthapuram	14	Golden Shower	1956-01-11
I006	Karnataka	Bangalore	31	Lotus	1956-01-11
I007	Uttar Pradesh	Lucknow	75	Palash	1950-01-24

1. select min(fdate) from states;
2. select count(districts) from states where districts>30;
3. select avg(districts) from states where sname like ‘%u%’;
4. select count(distinct fdate) from states;

Ans.:

[1]

min(fdate)

1949-03-30

[2]

count(districts)

4

[3]

avg(districts)

43.67

[4]

count(distinct fdate)

6

[44] Write output of queries given below based on table chips:

brand_name	flavour	price	qty
Lays	Onion	25	7
Bingo	Pudina	42	10
Pringles	Salty	37	8
Uncle Chips	Spicy	20	15
Doritos	Pudina	48	8
Cornitos	Spicy	28	18

1. Select BRAND_NAME, FLAVOUR from CHIPS where QTY like ‘%8’;
2. Select * from CHIPS where FLAVOUR=”SPICY” and PRICE > 20;
3. Select BRAND_NAME from CHIPS where price between 30 and 48 or QTY < 15;
4. Select count( distinct (flavour)) from CHIPS;
5. Select price *1.5 “New Price” from CHIPS where FLAVOUR = “PUDINA”;
6. Select distinct (BRAND_NAME) from CHIPS where brand_name like ‘%o%’order by BRAND_NAME desc;

Ans.:

[1]

brand_name	flavour
pringles	salty
doritos	pudina
cornitos	spicy

[2]

brand_name	flavour	price	qty
cornitos	spicy	28	18

[3]

brand_name

pringles

doritos

[4]

count( distinct (flavour))

4

[5]

New Price

63

72

[6]

Distinct (brand_name)

Bingo

Cornitos

Doritos

Most expected 4 marks questions computer science class 12 Unit 3 Database Management

[1] Consider the following tables participant and activity and answer the questions :

Table – Participant

ADMNO	NAME	HOUSE	ACTIVITYOCDE
A001	Sagar Patel	Red	AC001
A002	Kaushik Maheta	Blue	AC002
A003	Noor Joshi	Green	AC003
A004	Mahesh Joshi	Yellow	AC004
A005	Nutan Chauhan	Blue	AC001
A006	Mahek Patel	Yellow	AC004
A007	Sidhdharth Patel	Blue	AC003
A008	Gaurang Vyas	Green	AC004

Table – activity fields: activitycode, activityname, points

ACTIVITYCODE	ACTIVITYNAME	POINTS
AC001	Poem Recitation	120
AC002	Maths Quiz	150
AC003	Science Quiz	180
AC004	Sports	200

1. When the table ‘‘PARTICIPANT’’ was first created, the column ‘NAME’ was planned as the Primary key by the Programmer. Later a field ADMNO had to be set up as Primary key. Explain the reason.
2. Identify data type and size to be used for column ACTIVITYCODE in table ACTIVITY.
3. Write a query to display Activity Code along with the number of participants participating in each activity (Activity Code wise) from the table Participant.
4. How many rows will be there in the Cartesian product of the two tables in consideration here?
5. To display Names of Participants, Activity Code, and Activity Name in alphabetic ascending order of names of participants.
6. To display Names of Participants along with Activity Codes and Activity Names for only those participants who are taking part in Activities that have ‘quiz’ in their Activity Names and Points of activity are above 150.

[2] Consider the following tables SUPPLIER and ITEM and answer the questions

Table – Supplier

SNO	SNAME	AREA	EMAIL
1	A to Z Suppliers	Narol	a2zsupp@gmail.com
2	Rathi Brothers Company Pvt. Ltd.	Naroda	rathibrothers@gmail.com
3	Rushan Communications	Danilimda	rushan786@gmail.com
4	Apex Entreprise Pvt. Ltd.	Maninagar	apexmaninagar@gmail.com
5	Mahi Transport Co. Ltd.	Maninagar	mahimaninagar@gmail.com
6	Dhareja Travels	Naroda	dharejatravelsnaroda@gmail.com
7	Sameer Suppliers	Narol	sameersuppliers@gmail.com

Table – Item

INO	INAME	PRICE	SNO
I001	Cargo	28000	1
I002	Cartoon	500	2
I003	LG Mobiles	2600	3
I004	Truck on Rent	55000	1
I005	Reliance SIM	700	3
I006	Packing Material	8000	1
I007	Moterbikes	70000	4

1. Which column should be set as the Primary key for SUPPLIER table ?
2. Mr. Vijay, the Database Manager feels that Email column will not be the right choice for Primary key. State reason(s) why Email will not be the right choice.
3. Write the data type and size of INo column of ‘ITEM’ table.
4. To display names of Items, SNo and Names of Suppliers supplying those items for those suppliers who have stores located in Naroda.
5. To display Names of Items, SNo, Price and Corresponding names of their suppliers of all the items in ascending order of their Price.
6. To display Item Name wise, Minimum and Maximum Price of each item from the table item. i.e. display IName, minimum price and maximum price for each IName.)
7. What will be the number of rows in the Cartesian product of the above two tables?

[3] Consider the table given below:

Table – Faculty

TEACHERID	NAME	ADDRESS	STATE	PHONENUMBER
T001	Avinash	Ahmedabad	Gujarat	9825741256
T002	Akhilesh	Jaipur	Rajasthan	9824456321
T003	Shivansh	Mumbai	Maharashtra	9327045896
T004	Minaxi	New Delhi	Delhi	9012547863

Table – Course, Fields: coruseid, subject, teacherid, fee

COURSEID	SUBJECT	TEACHERID	FEE
1001	Computer Science	T001	6750
1002	Informatics Practices	T004	4550

1. Which column is used to relate the two tables?
2. Is it possible to have a primary key and a foreign key both in one table? Justify your answer with the help of table given above.
3. With reference to the above given tables, write commands in SQL for (i) and (ii) and output for (iii) :
   • (i) To display CourseId, TeacherId, Name of Teacher, Phone Number of Teachers living in Delhi.
   • (ii) To display TeacherID, Names of Teachers, Subjects of all teachers with names of Teachers starting with ‘S’.
   • (iii) SELECT CourseId, Subject,TeacherId,Name,PhoneNumber FROM Faculty,Course WHERE Faculty.TeacherId = Course.TeacherId AND Fee>=5000;

[4] Write commands in SQL for (1) to (4) and output for (5) and (6).

Table : Store

STOREID	NAME	LOCATION	CITY	NOOFEMPLOYEES	DATEOPENED	SALESAMOUNT
S01	BHAGYA LAXMI	SATELLITE	AHMEDABAD	7	2018-04-01	25000
S02	PARTH FASHION	AKOTA	BARODA	2	2010-07-15	45000
S03	KRISHNA SAREES	UMARWADA	SURAT	8	2020-08-13	85000
S04	SAMEER CLOTHES	RELIEF ROAD	AHMEDABAD	2	2012-06-02	78000

1. To display name, location, city, SalesAmount of stores in descending order of SalesAmount.
2. To display names of stores along with SalesAmount of those stores that have ‘fashion’ anywhere in their store names.
3. To display Stores names, Location and Date Opened of stores that were opened before 1st March, 2015.
4. To display total SalesAmount of each city along with city name.
5. SELECT distinct city FROM store;

[7] Consider the following DEPT and EMPLOYEE tables. Write SQL queries for (1) to (4) and find outputs for SQL queries (5) to (8).

Table:DEPT

DCODE	DEPARTMENT	LOCATION
10	AGRICULTURE	ANAND
20	MINES	NADIAD
30	TPP	KHEDA
40	MECHANICAL	AHMEDABAD

Table:EMP

ENO	NAME	DOJ	DOB	GENDER	DCODE
1111	MISKA	2020/03/01	1997/11/15	F	10
1112	AKSHAY	2018/06/05	1998/12/04	M	20
1113	NEEL	2021/07/01	2000/10/20	M	10
1114	ANKITA	2016/04/25	2001/10/27	F	30
1115	MOHIT	2016/12/22	2003/11/02	M	40

1. To display Eno, Name, Gender from the table EMPLOYEE in ascending order of Eno.
2. To display the Name of all the MALE employees from the table EMPLOYEE.
3. To display the Eno and Name of those employees from the table EMPLOYEE who are born between ‘1997-01-01’ and ‘1999-12-01’.
4. To count and display FEMALE employees who have joined after ‘1999-01-01’.
5. SELECT COUNT(*),DCODE FROM EMPLOYEE GROUP BY DCODE HAVING COUNT(*)>1;
6. SELECT DISTINCT DEPARTMENT FROM DEPT;
7. SELECT NAME,DEPARTMENT FROM EMPLOYEE E,DEPT D WHERE E.DCODE=D.DCODE AND ENO<1113
8. SELECT MAX(DOJ), MIN(DOB) FROM EMPLOYEE;

Watch the following video for more understanding:

Most expected Questions interface of python with MySQL

In this section of Most expected questions in Computer Science class 12, we are going to discuss questions from the interface of python with MySQL. Here we go!

Most important MCQs Interface of Python with MySQL

Let us begin with MCQs. here we go!

[1] Alpa wants to establish a connection between MySQL database and Python. Which of the following module except mysql.connector is used to fulfill her needs?

a) mysql.connect

b) pymysql

c) connect.mysql

d) connectmysql

[2] Krisha wants to connect her MySQL database with python. Suggest to her the method which she can use after importing mysql.connector module?

a) connect()

b) connection()

c) connector()

d) join()

[3] Rishi has given few functions. He needs to extract a function that cannot be used to fetch data from MySQL database which is connected with python. Assist him in selecting an appropriate method.

a) Mycur.fetch()

b) Mycur.fetchone()

c) Mycur.fetchmany(n)

d) Mycur.fetchall()

[4] Kunjan has assigned a task to find the statement which is used to get the number of rows fetched by execute method of the cursor. Assist him to find the same.

a) cursor.rowcount()

b) cursor.allrows()

c) cursor.rowscount()

d) cursor.countrows()

[5] Rearrange the steps for connecting MySQL database with python in the appropriate order.

i) create a cursor object

ii) open connection to a database

iii) execute the query and commit or fetch records

iv) import MySQL Connector

v) close the connection

a) i – ii – iii – iv – v

b) iv – ii – i – iii – v

c) v – i – iii – ii- iv

d) i – iii – v – ii – iv

[6] The connect method has few parameters. Which parameter is required to identify the name of the database server?

a) host

b) localhost

c) dbserver

d) server

[7] A special control structure is used to do the processing of data row by row. This control structure is

a) connection object

b) execute method

c) username and password

d) cursor object

[8] Which of the following is the correct statement:

a) import connector.mysql as cn

b) import MySQL.Connector as cn

c) import mysql.connector as cn

d) Import mysql.connectot AS cn

[9] The mysql.connector.connect() method returns

a) int object

b) connection object

c) list object

d) str object

[10] Observe the following code and select the correct statement with respect to create a cursor object?

import mysql.connector as ms
cn=ms.connect(host="localhost",user='root',passwd='root',database='test')
cr=____________________

a) cn.cursor()

b) cn.Cursor()

c) cursor(cn)

d) Cursor(cn)

[11] Krupa has created connection between mysql database and python. Now she wants to check the connection is properly established or not. Help her to select a proper function to accomplish her task.

a) connected()

b) isConnected()

c) isconnected()

d) is_connected()

[12] Which function is used to perform DML or DDL operations on database in interface of pyton with MySQL?

a) execute()

b) commit()

c) is_connected()

d) cursor()

[13] After completion of the work with interface of python with MySQL user need to clean up the work environment. Which function is used to perform this task?

a) clear()

b) clean()

c) close()

d) destroy()

[14] The fetchall() function will return all the records as

a) Only lists

b) Tuple of list

c) List of lists

d) List of tuples

[15] What will be returned by fetchone() method?

a) All values in str

b) All values in list or tuple

c) All values in dictionary

d) None of these

[16] State True or False: “The fetechone() method returns None if there are no more records in database.”

[17] Which placeholder is required to be placed for string parameters in string template while writing query to exdcute() method?

a) str

b) %s

c) %str

d) %string

[18] The fetchmany(n) returns any n no. of rows from database.

a) Yes, any n rows randomly

b) no, sorts first then top n rows

c) no, only top n rows from table as its present in table

d) None of these

[19] When fetchone() method is used, the cursor moves to ____________ record immediately after getting the specified row.

a) next record

b) last record in the table (end of table)

c) first record

d) previous record

[20] A string template refers to

i) MySQL Command

ii) MySQL Function

iii) string containing a mixture of one or more format codes

iv) a string consists of text with the f % v

a) i) and ii)

b) i and iii)

c) iii) and iv)

d) ii) and iv)

[21] After executing the insert, update, or delete statement you must use which of the following function?

a) commit()

b) save()

c) update()

d) store()

Most important 2/3 Marks Questions Interface of Python with MySQL

[1] Nisha is trying to create a project on python. Where she wants to store the records in a database. She learnt about front-end and back-end, But forget what it means right now. Help her by giving definition of front-end and backend.

[2] What is DB-API?

[3] What does DB-API include?

[4] Man wants to install the mysql connector. Suggest steps to install the same.

[5] Prakash has installed mysql connector. Now he wants to check whether its properly installed or not. Suggest python command to do this task.

[6] Name any two python mysql connector modules.

[7] What are the main components of mysql.connector module?

[8] What do you mean by a connection?

[9] What do you mean by cursor object?

[10] What are the parameters of mysql.connector.connect method?

[11] Neel is trying to write the connect method. Help him by filling the given gaps:

import ____________ as ms
cn=ms.________(host=localhost,user='root',passwd='root',database='school') 
cr=cn._____()
cn.______()

[12] Fill the proper words in the following code snippet:

cn=mysql.connector.connect(_______=localhost,________='root',________='root',______='school') 

[13] Babita wants to insert a record into the table using a python MySQL connector. Suggest two methods that are used to execute the query using the cursor object.

[14] What are the methods used to read data from SQL tables?

[15] Differentiate between fetchone() and fetchmany().

[16] Is rowcount method? Explain in short.

[17] Consider the following table: IPL2022

Rank	Batter	Runs	Team
1	Jos Buttler	863	RR
2	KL Rahul	616	LSG
3	Quinton de Kock	508	LSG
4	Hardik Pandya	487	GT
5	Shubman Gill	483	GT

Observe the following given code and write the output:

import mysql.connector as ms
cn=ms.connect(host='localhost',user='root',passwd='root',database='IPL')
cr=cn.cursor()
cr.execute("seleect * from IPL2022")
r=cr.fetchone()
r=cr.fetchone()
r=cr.fetchone()
data=int(r[2])
print(data*2)

[18] Consider the table given in the above question and write the for this code snippet:

import mysql.connector as ms
cn=ms.connect(host='localhost',user='root',passwd='root',database='IPL')
cr=cn.cursor()
cr.execute("seleect * from IPL2022")
r=cr.fetchone()
print("No. of records fetched:",cr.rowcount)
r=cr.fetchmany(2)
print("No. of records fetched:",cr.rowcount)

[19] Consider the tabe given in question no. 17 and write python code to display the top 3 run-scorer.

[20] Consider the table given in question 17 and write python code to display details for those batsmen who score less than 500 runs.

[21] Write python code to insert this record: (6,’David Miller’,481,’GT’)

[22] Write python code to update short team name GT to full team name Gujarat Titans.

[23] Write code to delete record of David Miller.

Watch this video for practical understanding:

[24] The partial code is given to check whether the connection between the interface of python with MySQL is established or not. Fill in the blanks with appropriate functions/statements for given statements:

Note the following to establish connectivity between Python and MYSQL:

• Username is root
• Password is root
• Database name – Transport

V_ID	Name	Model	Price
integer	varchar	integer	integer

import ____________ as msql #Statement 1
cn=msql.___________(_______,________,________,_______) #Statement 2
if cn.__________:   # Statement 3
    print("Successfully Connected...")
else:
  print("Something went wrong...")

Write the missing statements as per the given instructions:

1. Write the module name required in #Statement 1
2. Complete the code with the name of a function and parameters in #Statement 2
3. Write a function to check whether the connection is established or not in #Statement 3

[25] Consider the database and parameters given in [24] and complete the code below given partial code of fetching records having vehicles model after 2010.

import mysql.connector as mysql
con1=mysql.connect(host="localhost",
                   user="root", 
                   password="root", 
                   database="Transport")
_______________ #Statement 1 
print("Models after 2010 : ")
q="Select * from vehicle where model>2010"
_______________________ #Statement 2
data= _________________ #Statement 3
for rec in data:
        print(rec)

Write the following missing statements to complete the code:

1. Statement 1 – to create the cursor object
2. Statement 2 – to execute the query that extracts records of those vehicles whose model is greater than 2010.
3. Statement 3 – to read the complete result of the query into the object named data.

Answer:

Watch this video to understand with practical explanation:

[26] Consider the following facts for connecting an interface of python with MySQL and complete the given partial code given for inserting a record into the database table:

The table structure of student is as follows:

RollNo	Name	Standard	Marks
integer	varchar	integer	float

Note the following to establish connectivity between Python and MySQL:

• Username is root
• Password is root
• The table exists in a “school” database.
• The details (RollNo, Name, Standard, and Marks) are to be accepted by the user.

import mysql.connector as mysql
con1=mysql.connect(host="localhost",
                   user="root", 
                   password="root", 
                   database="school")
mycursor = con1.cursor() 
rno=int(input("Enter Roll Number :: "))
name=input("Enter name :: ")
std=int(input("Enter class :: "))
marks=int(input("Enter Marks :: "))
querry=________________________________ #Statement 1
______________________ #Statement 2
______________________ # Statement 3
con1.close()
print("Data Added successfully")

Write the following missing statements to complete the code:
Statement 1 – query insert records with all the variables
Statement 2 – to execute the command that inserts the record in the table Student.
Statement 3 – to add the record permanently to the database

Answer:

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Important PYQs Computer Science Class 12

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