Question 1

Question 26The correct syntax of seek() is :file_object.seek(offset[, reference_point])seek(offset[, reference_point])seek(offset, file_object)seek.file_object(offset)

Accepted Answer

file_object.seek(offset[, reference_point])Reason — The syntax of seek() function is <file-object>.seek(offset[, mode]).

Source: This question is from File Handling, Computer Science &mdash; Class 12, CBSE Board.
Key Concepts CoveredThis question tests your understanding of the following concepts from the chapter File Handling: Question, Correct, Syntax, Seek, File, Object. These are fundamental topics in Computer Science that students are expected to master as part of the CBSE Class 12 curriculum.A thorough understanding of these concepts will help you answer similar questions confidently in your CBSE examinations. These topics are frequently tested in both objective and subjective sections of Computer Science papers. We recommend revising the relevant section of your textbook alongside practising these solved examples to build a strong foundation.
How to Approach MCQsMultiple choice questions test your ability to quickly recall facts and apply concepts. Read all options carefully before selecting your answer. Use the process of elimination to rule out clearly incorrect options first. If two options seem similar, look for the subtle difference that makes one more accurate. For numerical MCQs, verify your answer by substituting it back into the problem.
Key Points to RememberWrite programs with proper indentation and comments.
Trace through your code with sample inputs to verify correctness.
Explain the logic behind each step of your solution.
Familiarise yourself with common library functions and methods.
Related Questions from File HandlingQ1: Question 1 Write a program that reads a text file and creates another file that is identical except...
Q10: Question 10 Write a method/function DISPLAYWORDS() in python to read lines from a text file...
Q11: Question 11 Write a program that reads characters from the keyboard one by one. All lower case...
Q12: Question 12 Write a function in Python to count and display the number of lines starting with...
Q13: Question 13 How many file objects would you need to create to manage the following situations ?...
Practice more questions from File Handling &mdash; Computer Science, Class 12 CBSE

Question 2

Question 9What are the advantages of saving data in :(i) binary form(ii) text form(iii) csv files ?

Accepted Answer

(i) The advantages of saving data in binary form are as follows:Efficiency — Binary files store data in a compact binary format, which can lead to smaller file sizes compared to text-based formats. Binary form is efficient for storing raw binary data.Speed — Reading and writing binary data can be faster than text-based formats because there is no need for encoding or decoding operations.Data Integrity — Binary files preserve the exact binary representation of data without any loss of information.(ii) The advantages of saving data in text form are as follows:Human Readability — Text-based formats, such as plain text files, are human-readable, making them easy to inspect and edit using a text editor.Interoperability — Text files can be easily shared and processed across different platforms and programming languages.Compatibility — Text-based formats are widely supported by various software applications and systems, making them a versatile choice for data interchange and communication.(iii) The advantages of saving data in CSV files are as follows:Tabular Data Representation — CSV (Comma-Separated Values) files provide a simple and standardized way to represent tabular data, with rows and columns separated by commas.Simplicity — CSV files are easy to create, parse, and manipulate using spreadsheet software.Flexibility — CSV files can store a wide range of data types, including numbers, strings, and dates.Interoperability — CSV files are supported by many software applications, databases, and programming languages, allowing for seamless integration and data exchange between different systems.

Question 3

Question 13How many file objects would you need to create to manage the following situations ? Explain.(i) to process three files sequentially(ii) to merge two sorted files into a third file.

Accepted Answer

(i) To process three files sequentially — In this scenario, where we need to process three files sequentially, we would need a single file object, as we can reuse a single file object by opening then processing and closing it for each file sequentially.For example :f = open("file1.txt", "r")
# Process file 1 using f
f.close()

f = open("file2.txt", "r")
# Process file 2 using f
f.close()

f = open("file3.txt", "r")
# Process file 3 using f
f.close()Here, we are reusing the f file object three times sequentially. We start by opening file1 in read mode and store its file handle in file object f. We process file1 and close it. After that, same file object f is again reused to open file 2 in read mode and process it. Similarly, for file3 also we reuse the same file object f.(ii) To merge two sorted files into a third file — In this scenario, where we need to merge two sorted files into a third file, we would need three file objects, one for each input file and one for the output file. We would open each input file for reading and the output file for writing. Then, we would read data from the input files, compare the data, and write the merged data to the output file. Finally, we would close all three files after the merging operation is complete.For example :f1 = open("file1.txt", "r")
f2 = open("file2.txt", "r")
f3 = open("merged.txt", "w")
# Read line from f1
# Read line from f2
# Process lines
# Write line to f3
f1.close()
f2.close()
f3.close()

Question 4

Question 2If the file 'poemBTH.txt' contains the following poem (by Paramhans Yoganand) :God made the Earth;
Man made confining countries
And their fancy-frozen boundaries.
But with unfound boundLess Love
I behold the borderLand of my India
Expanding into the World.
HaiL, mother of religions, Lotus, scenic beauty, and sages!
Then what outputs will be produced by both the code fragments given in question1.

Accepted Answer

(a)my_file = open('poemBTH.txt', 'r')
my_file.read()OutputGod made the Earth;
Man made confining countries
And their fancy-frozen boundaries.
But with unfound boundLess Love
I behold the borderLand of my India
Expanding into the World.
HaiL, mother of religions, Lotus, scenic beauty, and sages!
ExplanationThis code reads the entire content of the file poemBTH.txt into a single string. Since no specific number of characters is specified, it will read until the end of the file (EOF) is reached.(b)my_file = open('poemBTH.txt', 'r') 
my_file.read(100)OutputGod made the Earth;
Man made confining countries
And their fancy-frozen boundaries.
But with unfound 
ExplanationThis code reads the first 100 characters from the file "poemBTH.txt" into a string. It is important to note that the newline at the end of each line will also be counted as a character.

Question 5

Question 3Consider the file poemBTH.txt given above (in previous question). What output will be produced by following code fragment ?obj1 = open("poemBTH.txt", "r")
s1 = obj1.readline()
s2.readline(10)
s3 = obj1.read(15)
print(s3)
print(obj1.readline())
obj1.close()

Accepted Answer

The code will result in an error because at line 3 there is a syntax error. The correct syntax is s2 = obj1.readline().ExplanationThe corrected code will be:obj1 = open("poemBTH.txt", "r")
s1 = obj1.readline()
s2 = obj1.readline()
s3 = obj1.read(15)
print(s3)
print(obj1.readline())
obj1.close()OutputAnd their fancy
-frozen boundaries.
obj1 = open("poemBTH.txt", "r") — This line opens the file named poemBTH.txt in read mode ("r") and assigns the file object to the variable obj1.s1 = obj1.readline() — This line reads the first line from the file obj1 and assigns it to the variable s1.s2 = obj1.readline() — This line reads the next line from the file obj1, starting from the position where the file pointer currently is, which is the beginning of the second line (from the previous readline() call). Then assigns it to the variable s2.s3 = obj1.read(15) — This line reads the next 15 characters from the file obj1, starting from the position where the file pointer currently is, which is the beginning of third line (from the previous readline() call) and assigns them to the variable s3.print(s3) — This line prints the contents of s3.print(obj1.readline()) — This line attempts to read the next line from the file obj1 and print it. However, since the file pointer is already ahead by 15 characters (from the previous read(15) call), this line will start reading from where the file pointer is currently positioned i.e., from "-" up to end of line.obj1.close() — This line closes the file obj1.

Question 6

Question 7Consider the file "contacts.csv" created in above Q. and figure out what the following code is trying to do?name = input("Enter name :")
file = open("contacts.csv", "r")
for line in file:
    if name in line:
       print(line)

Accepted Answer

The code asks the user to enter a name. It then searches for the name in "contacts.csv" file. If found, the name and phone number are printed as the output.Explanationname = input("Enter name :") — This line prompts the user to enter a name through the console, and the entered name is stored in the variable name.file = open("contacts.csv", "r") — This line opens the file contacts.csv in read mode and assigns the file object to the variable file.for line in file: — This line initiates a for loop that iterates over each line in the file handle (file represents the opened file object), which enables interaction with the file's content. During each iteration, the current line is stored in the variable line.if name in line: — Within the loop, it checks if the inputted name exists in the current line using the in operator.print(line) — If the name is found in the current line, this line prints the entire line to the console.

Question 7

Question 8Consider the file poemBTH.txt and predict the output of following code fragment. What exactly is the following code fragment doing ?f = open("poemBTH.txt", "r")
nl = 0
for line in f:
    nl += 1
print(nl)

Accepted Answer

The code is calculating the number of lines present in the file poemBTH.txt.Output7
Explanationf = open("poemBTH.txt", "r") — This line opens a file named poemBTH.txt in read mode ("r") and assigns the file object to the variable f.nl = 0 — This line initializes a variable nl to 0.for line in f: — By iterating over the file handle using a for loop as shown, we can read the contents of the file line by line.nl += 1 — Within the for loop, this statement increments the value of nl by 1 for each iteration, effectively counting the number of lines in the file.print(nl) — After the for loop completes, this statement prints the value of nl, which represents the total number of lines in the file.

Question 8

Question 14(b)Identify the error in the following code.import csv
f = open('attendees1.csv')
csv_f = csv.reader()
for row in csv_f:
    print(row)

Accepted Answer

import csv f = open('attendees1.csv') #error 1 csv_f = csv.reader() #error 2 for row in csv_f: print(row)To use the csv.reader() function, the file should be opened in read mode ('r').The reader object should be in syntax = csv.reader().The corrected code is :import csv f = open('attendees1.csv', 'r') csv_f = csv.reader(f) for row in csv_f: print(row)

Question 9

Question 1Write a program that reads a text file and creates another file that is identical except that every sequence of consecutive blank spaces is replaced by a single space.

Accepted Answer

Let the file "input.txt" include the following sample text:In    the beginning  there  was    chaos.
Out of  the chaos  came order.
The universe  began to take shape.
Stars  formed  and galaxies were  born.
Life   emerged  in the  vast  expanse.
with open("input.txt", 'r') as f:
    with open("output.txt", 'w') as fout:
        for line in f:
            modified_line = ' '.join(line.split())
            fout.write(modified_line + '
')The file "output.txt" includes following text:In the beginning there was chaos.
Out of the chaos came order.
The universe began to take shape.
Stars formed and galaxies were born.
Life emerged in the vast expanse.

Question 10

Question 4Write a program to count the words "to" and "the" present in a text file "Poem.txt".

Accepted Answer

Let the file "Poem.txt" include the following sample text:To be or not to be, that is the question.
The quick brown fox jumps over the lazy dog.
To infinity and beyond!
The sun sets in the west.
To be successful, one must work hard.
to_count = 0
the_count = 0

with open("Poem.txt", 'r') as file:
    for line in file:
        words = line.split()
        for word in words:
            if word.lower() == 'to':
                to_count += 1
            elif word.lower() == 'the':
                the_count += 1

print("count of 'to': ", to_count)
print("count of 'the': ", the_count)Outputcount of 'to': 4
count of 'the': 5

Question 11

Question 5Write a function AMCount() in Python, which should read each character of a text file STORY.TXT, should count and display the occurrence of alphabets A and M (including small cases a and m too).Example :If the file content is as follows :Updated informationAs simplified by official websites.The EUCount() function should display the output as :A or a : 4M or m : 2

Accepted Answer

Let the file "STORY.TXT" include the following sample text:Updated information
As simplified by official websites.
def AMCount(file_path):
    count_a = 0
    count_m = 0
    with open(file_path, 'r') as file:
        ch = ' '
        while ch:
            ch = file.read(1)
            ch_low = ch.lower()
            if ch_low == 'a':
                count_a += 1
            elif ch_low == 'm':
                count_m += 1

print("A or a:", count_a)
    print("M or m:", count_m)

AMCount("STORY.TXT")OutputA or a: 4 
M or m: 2

Question 12

Question 6Write a program to count the number of upper-case alphabets present in a text file "Article.txt".

Accepted Answer

Let the file "Article.txt" include the following sample text:PYTHON is a Popular Programming Language.
with open("Article.txt", 'r') as file:
    text = file.read()
    count = 0
    for char in text:
        if char.isupper():
            count += 1

print(count)Output9

Question 13

Question 10Write a method/function DISPLAYWORDS() in python to read lines from a text file STORY.TXT, and display those words, which are less than 4 characters.

Accepted Answer

Let "STORY.TXT" file contain the following text:Once upon a time, there was a little boy named Jay
He had a dog named Leo
def DISPLAYWORDS(file_name):
    with open(file_name, 'r') as file:
        for line in file:
            words = line.split()
            for word in words:
                if len(word) < 4:
                    print(word)
        for line in file:
            words = line.split()
            for word in words:
                if len(word) < 4:
                    print(word)

DISPLAYWORDS("STORY.TXT")Outputa
was
a
boy
Jay
He
had
a
dog
Leo

Question 14

Question 11Write a program that reads characters from the keyboard one by one. All lower case characters get stored inside the file LOWER, all upper case characters get stored inside the file UPPER and all other characters get stored inside file OTHERS.

Accepted Answer

lower_file = open("LOWER.txt", 'w')
upper_file = open("UPPER.txt", 'w')
others_file = open("OTHERS.txt", 'w')
ans = 'y'
while ans == 'y':
    char = input("Enter a character: ")
    if char.islower():
        lower_file.write(char + "
")
    elif char.isupper():
        upper_file.write(char + "
")
    else:
        others_file.write(char + "
")
    ans = input("Want to enter a character? (y/n): ")
lower_file.close()
upper_file.close()
others_file.close()OutputEnter a character: e
Want to enter a character? (y/n): y
Enter a character: A
Want to enter a character? (y/n): y
Enter a character: D
Want to enter a character? (y/n): y
Enter a character: c
Want to enter a character? (y/n): y
Enter a character: 7
Want to enter a character? (y/n): y
Enter a character: @
Want to enter a character? (y/n): n
The file "LOWER.txt" includes:e
c
The file "UPPER.txt" includes:A
D
The file "OTHERS.txt" includes:7
@

Question 15

Question 12Write a function in Python to count and display the number of lines starting with alphabet 'A' present in a text file "LINES.TXT". e.g., the file "LINES.TXT" contains the following lines:A boy is playing there.
There is a playground.
An aeroplane is in the sky.
Alphabets & numbers are allowed in password.
the function should display the output as 3.

Accepted Answer

The file "LINES.TXT" contains the following lines:A boy is playing there.
There is a playground.
An aeroplane is in the sky.
Alphabets & numbers are allowed in password.
def count_lines(file_name):
    count = 0
    with open(file_name, 'r') as file:
        for line in file:
            if line.strip().startswith('A'):
                count += 1
    print(count)

count_lines("LINES.TXT")Output3

Question 16

Question 14Write a program that will create an object called filout for writing, associate it with the filename STRS.txt. The code should keep on writing strings to it as long as the user wants.

Accepted Answer

with open('STRS.txt', 'w') as filout:
    ans = 'y'
    while ans == 'y':
        string = input("Enter a string: ")
        filout.write(string + "
")  
        ans = input("Want to enter more strings?(y/n)...")    OutputEnter a string: Hello
Want to enter more strings?(y/n)...y
Enter a string: world!
Want to enter more strings?(y/n)...n
The file "STRS.txt" includes:Hello
world!

Question 17

Question 16Consider the following definition of dictionary Staff, write a method in python to search and display content in a pickled file staff.dat, where Staffcode key of the dictionary is matching with 'S0105'.Staff = {'Staffcode': ..............., 'Name' = ...............}

Accepted Answer

Let the file "staff.dat" include following data:Staff1 = {'Staffcode': 'S0102', 'Name': 'Sanya'}
Staff2 = {'Staffcode': 'S0104', 'Name': 'Anand'}
Staff3 = {'Staffcode': 'S0105', 'Name': 'Aditya'}
import pickle

def search_and_display_staff(staff_code):
    found = False

try:
        file = open("staff.dat", "rb")
        
        while True:
            staff_data = pickle.load(file)
            if staff_data['Staffcode'] == staff_code:
                print("Staffcode:", staff_data['Staffcode'])
                print("Name:", staff_data['Name'])
                found = True
                
    except EOFError:
        if found == False:
            print("End of file reached. No such records found.")
        else:
            print("Search Successful")
        file.close()

search_and_display_staff('S0105')OutputStaffcode: S0105
Name: Aditya

Question 18

Question 17Considering the following definition of dictionary COMPANY, write a method in Python to search and display the content in a pickled file COMPANY.DAT, where CompID key of the dictionary is matching with the value '1005'.Company = {'CompID' = ........., 'CName' = ........., 'Turnover' = .........}

Accepted Answer

Let the file "COMPANY.DAT" include following data:Company1 = {'CompID': '1001', 'CName': 'ABC', 'Turnover': 500000}
Company2 = {'CompID': '1003', 'CName': 'DEF', 'Turnover': 600000}
Company3 = {'CompID': '1005', 'CName': 'LMN', 'Turnover': 900000}
import pickle

def company(comp_id):
    found = False

try:
        file = open("COMPANY.DAT", "rb")
        while True:
            company_data = pickle.load(file)
            if company_data['CompID'] == comp_id:
                print("Company ID:", company_data['CompID'])
                print("Company Name:", company_data['CName'])
                print("Turnover:", company_data['Turnover'])
                found = True

except EOFError:
        if found == False:
            print("End of file reached. No such records found.")
        else:
            print("Search Successful")
        file.close()

company('1005')OutputCompany ID: 1005
Company Name: LMN
Turnover: 900000

Question 19

Question 18Write a function to search and display details of all trains, whose destination is "Delhi" from a binary file "TRAIN.DAT". Assuming the binary file is containing the objects of the following dictionary type:Train = {'Tno': ..............., 'From': ...............,'To': ...............}

Accepted Answer

Let the dictionary contained in file "TRAIN.DAT" be as shown below:Train1 = {'Tno': '1234', 'From': 'Mumbai', 'To': 'Delhi'}
Train2 = {'Tno': '5678', 'From': 'Chennai', 'To': 'Delhi'}
Train3 = {'Tno': '9012', 'From': 'Kolkata', 'To': 'Mumbai'}
Train4 = {'Tno': '3456', 'From': 'Delhi', 'To': 'Bangalore'}
Train5 = {'Tno': '7890', 'From': 'Pune', 'To': 'Delhi'}
import pickle

def search_trains():
    found = False

try:
        file = open("TRAIN.DAT", "rb")

while True:
            trains = pickle.load(file)
            if trains['To'] == "Delhi":
                print("Train no: ", trains['Tno'])
                print("From: ", trains['From'])
                print("To: ", trains['To'])
                found = True
                
    except EOFError:
        if found == False:
            print("End of file reached. No such records found.")
        else:
            print("Search Successful")
        file.close()

search_trains()OutputTrain no:  1234
From:  Mumbai
To:  Delhi
Train no:  5678
From:  Chennai
To:  Delhi
Train no:  7890
From:  Pune
To:  Delhi
Search Successful

Question 20

Question 19A binary file "Book.dat" has structure [BookNo, Book_Name, Author, Price].(i) Write a user defined function CreateFile() to input data for a record and add to Book.dat.(ii) Write a function CountRec(Author) in Python which accepts the Author name as parameter and count and return number of books by the given Author are stored in the binary file "Book.dat"

Accepted Answer

Let the file "Book.dat" include following data:Book1 = [1001, Midnight's Children, Salman Rushdie, 29.99]
Book2 = [1004, A Suitable Boy, Vikram Seth, 59.9]
Book3 = [1003, The White Tiger, Aravind Adiga, 49.5]
Book4 = [1002, The Satanic Verses, Salman Rushdie, 39.23]
import pickle

def CreateFile():
        file = open("Book.dat", "ab")
        BookNo = int(input("Enter Book Number: "))
        Book_Name = input("Enter Book Name: ")
        Author = input("Enter Author Name: ")
        Price = float(input("Enter Price: "))
        record = [BookNo, Book_Name, Author, Price]
        pickle.dump(record, file)
        file.close()
    
def CountRec(authorName):
    count = 0
    found = False
    try:
        file = open("Book.dat", "rb")
        while True:
            record = pickle.load(file)
            if record[2] == authorName:
                count += 1
                found = True

except EOFError:
        if found == False:
            print("End of file reached. No such records found.")
        else:
            print("Search successful")
        file.close()
        return count

CreateFile()
author = input("Enter Author name to count books: ")
print("Number of books by", author, ":", CountRec(author))OutputEnter Book Number: 1008
Enter Book Name: Three Thousand Stiches
Enter Author Name: Sudha Murty
Enter Price: 200
Enter Author name to count books: Salman Rushdie
Search successful
Number of books by Salman Rushdie : 2

File Handling

Multiple Choice Questions

Type A Short Answer Questionsconceptual Questions

Type B Application Based Questions

Type C Programming Practiceknowledge Based Questions