List of top Computer Science Questions on Programming in Python asked in CBSE CLASS XII

A file PASSENGERS.DAT stores the records of passengers using the following structure:
PNR, PName, BRDSTN, DESTN, FARE

Where:
- PNR — Passenger Number (string type)
- PName — Passenger Name (string type)
- BRDSTN — Boarding Station Name (string type)
- DESTN — Destination Station Name (string type)
- FARE — Fare amount for the journey (float type)

Write user-defined functions in Python for the following tasks:

(i) Create() – to input data for passengers and write it in the binary file PASSENGERS.DAT.
(ii) SearchDestn(D) – to read contents from the file PASSENGERS.DAT and display the details of those Passengers whose DESTN matches with the value of D.
(iii) UpdateFare() – to increase the fare of all passengers by 5% and rewrite the updated records into the file PASSENGERS.DAT.

A CSV file "P_record.csv" contains the records of patients in a hospital. Each record of the file contains the following data:
- Name of a patient
- Disease
- Number of days patient is admitted
- Amount

For example, a sample record of the file may be:
["Gunjan", "Jaundice", 4, 15000]

Write the following Python functions to perform the specified operations on this file:

(i) Write a function read_data() which reads all the data from the file and displays the details of all the 'Cancer' patients.

(ii) Write a function count_rec() which counts and returns the number of records in the file.

Write the output on execution of the following Python code:

def Change(X):
    for K, V in X.items():
        L1.append(K)
        L2.append(V)

D = {1: "ONE", 2: "TWO", 3: "THREE"}
L1 = []
L2 = []
Change(D)
print(L1)
print(L2)
print(D)

Predict the output of the following code:

def ExamOn(mystr):
    newstr = ""
    count = 0
    for i in mystr:
        if count % 2 != 0:
            newstr = newstr + str(count - 1)
        else:
            newstr = newstr + i.lower()
        count += 1
    newstr = newstr + mystr[:2]
    print("The new string is:", newstr)

ExamOn("GenX")

Write the following user-defined functions in Python:

(i) push_trail(N, myStack): Here N and myStack are lists, and myStack represents a stack.
The function should push the last 5 elements from the list N onto the stack myStack.
Assume that N contains at least 5 elements.

(ii) pop_one(myStack): The function should pop an element from the stack myStack, and return this element.
If the stack is empty, then the function should display the message 'Stack Underflow', and return None.

(iii) display_all(myStack): The function should display all the elements of the stack myStack, without deleting them.
If the stack is empty, the function should display the message 'Empty Stack'.

A stack, named ClrStack, contains records of some colors. Each record is represented as a tuple containing four elements — ColorName, RED, GREEN, BLUE. ColorName is a string, and RED, GREEN, BLUE are integers. For example, a record in the stack may be ('Yellow', 237, 250, 68).

Write the following user-defined functions in Python to perform the specified operations on ClrStack:

(i) push_Clr(ClrStack, new_Clr): This function takes the stack ClrStack and a new record new_Clr as arguments and pushes this new record onto the stack.

(ii) pop_Clr(ClrStack): This function pops the topmost record from the stack and returns it. If the stack is already empty, the function should display the message "Underflow".

(iii) isEmpty(ClrStack): This function checks whether the stack is empty. If the stack is empty, the function should return True, otherwise the function should return False.

Write a Python function that displays all the words starting and ending with a vowel from a text file "Report.txt".
The consecutive words should be separated by a space in the output.
For example, if the file contains:
Once there was a wise man in a village.
He was an awesome story-teller.
He was able to keep people anchored while listening to him.
Then the output should be:
Once a a awesome able

Write a Python function that displays all the lines containing the word 'vote' from a text file "Elections.txt".
For example, if the file contains:
In an election many people vote to choose their representative.
The candidate getting the maximum share of votes stands elected.
Normally, one person has to vote once.
The process of voting may vary with time and region.
Then the output should be:
In an election many people vote to choose their representative.
Normally, one person has to vote once.

The code given below accepts N as an integer argument and returns the sum of all integers from 1 to N. Observe the following code carefully and rewrite it after removing all syntax and logical errors. Underline all the corrections made.

def Sum(N):
    S = 0
    for I in range(1, N + 1):
        S = S + I
    return S

print(Sum(10))

What possible output from the given options is expected to be displayed when the following code is executed?

import random
Cards = ["Heart", "Spade", "Club", "Diamond"]
for i in range(2):
    print(Cards[random.randint(1, i+2)], end="#")

Consider the following dictionaries, D and D1:
D = { "Suman": 40, "Raj": 55, "Raman": 60 }
D1 = { "Aditi": 30, "Amit": 90, "Raj": 20 }

(Answer using built-in Python functions only)

(i)
(a) Write a statement to display/return the value corresponding to the key "Raj" in the dictionary D.

OR

(b) Write a statement to display the length of the dictionary D1.

(ii)
(a) Write a statement to append all the key-value pairs of the dictionary D to the dictionary D1.

OR

(b) Write a statement to delete the item with the given key "Amit" from the dictionary D1.

Write one example of each of the following in Python:
(i) Syntax Error
(ii) Implicit Type Conversion

What does the return statement do in a function? Explain with the help of an example.

Assertion (A): For a binary file opened using 'rb' mode,
the pickle.dump() method will display an error.
Reason (R): The pickle.dump() method is used to read from a binary file.

Which of the following built-in function/method returns a dictionary?

Consider the statements given below and then choose the correct output from the given options:

N = '5'
try:
    print('WORD' + N, end='#')
except:
    print('ERROR', end='#')
finally:
    print('OVER')

Consider the statements given below and then choose the correct output from the given options:

def Change(N):
    N = N + 10
    print(N, end='$$')

N = 15
Change(N)
print(N)

Consider the statements given below and then choose the correct output from the given options:

D = {'S01': 95, 'S02': 96}
for I in D:
    print(I, end='#')

Which of the following operator evaluates to True if the variable on either side of the operator points towards the same memory location and False otherwise?

Consider the statements given below and then choose the correct output from the given options:
L = ['TIC', 'TAC']
print(L[::-1])

Identify the invalid Python statement out of the following options:

Which of the following is the correct identifier?

Identify the correct output of the following code snippet:
game = "Olympic2024"
print(game.index("C"))

What will be the output of the following statement?
print(14%3**2*4)

State True or False: “A Python List must always contain all its elements of same data type.”