• Hajipur, Bihar, 844101

☰
❮
❯

Python

Introduction to Python

Python Basics

Cotrol Structures

Data Structures

Date and Time

Functions and Module

File Handling

Python OOP

Advanced Concepts

Python DSA

Searching Algorithms

Sorting Algorithms

Python Write/Create Files

← Previous Next →

In Python, you can create and write to files using the open() function with the modes "w", "a", or "x".

🔹 w – Write (Overwrite)

f = open("demo.txt", "w")
f.write("This is a new line.")
f.close()

✅ If the file doesn't exist, it will be created.
⚠️ If it exists, it will overwrite everything.

🔹 a – Append (Add at End)

f = open("demo.txt", "a")
f.write("\nAnother line added.")
f.close()

✅ Adds content to the end without deleting existing data.

🔹 x – Create (Error if File Exists)

f = open("newfile.txt", "x")
f.write("File created using x mode.")
f.close()

❌ Raises an error if the file already exists.

🔹 Write Multiple Lines

f = open("demo.txt", "w")
f.writelines(["Line 1\n", "Line 2\n", "Line 3\n"])
f.close()

✅ writelines() takes a list of strings.

🔹 Write in Binary

with open("binaryfile.bin", "wb") as f:
    f.write(b"This is binary data.")

🔹 Best Practice: Use with

with open("demo.txt", "w") as f:
    f.write("Safe writing using with.")

✅ File automatically closes after use.

🔹 Check If File Exists Before Writing

import os

if not os.path.exists("demo.txt"):
    f = open("demo.txt", "w")
    f.write("File created safely.")
    f.close()

Practice Questions

Q1. Write a Python program to write "Hello World" to a file using "w" mode.

Q2. Write a Python program to create a file only if it doesn’t exist using "x" mode.

Q3. Write a Python program to append a new line to notes.txt using "a" mode.

Q4. Write a Python program to overwrite the contents of log.txt with a new message using "w" mode.

Q5. Write a Python program to write multiple lines to a file using the writelines() method.

Q6. Write a Python program to write a binary string to a .bin file using "wb" mode.

Q7. Write a Python program to use with open() to write to a file safely and automatically close it.

Q8. Write a Python program to check if a file exists before writing to it using "w" mode, using os.path.exists().

Q9. Write a Python program to create a function that takes user input and saves it to a file.

Q10. Write a Python program to append today’s date to a file, using the datetime module.

Python Write/Create Files Quiz

Q1: What does "w" mode do in open()?

A. Reads file
B. Appends file
C. Overwrites or creates file
D. Deletes file

Q2: What happens if the file exists and you open it in "w" mode?

A. It appends
B. Nothing happens
C. It gets deleted
D. It is overwritten

Q3: Which mode is used to create a file only if it does not exist?

A. "c"
B. "x"
C. "new"
D. "r+"

Q4: What does writelines() accept?

A. A string
B. A list of strings
C. An integer
D. Nothing

Q5: What mode should be used to append data?

A. "r"
B. "w"
C. "a"
D. "x"

Q6: What does "wb" mode mean?

A. Write in blocks
B. Write binary
C. Write buffered
D. Write back

Q7: What is the purpose of with open()?

A. It auto-closes the file
B. It loops through files
C. It reads hidden files
D. It encrypts the file

Q8: What does open("file.txt", "x") do if file exists?

A. Overwrites
B. Appends
C. Raises error
D. Clears file

Q9: Which function writes text to a file?

A. writefile()
B. writeline()
C. write()
D. put()

Q10: How to write multiple lines at once?

A. writeall()
B. writemany()
C. writelines()
D. joinwrite()
← Previous Next →
Login
Go Back Top