File handling is a core part of many real-world applications—whether you're storing data, reading configuration files, or writing logs. Python makes file operations straightforward with its built-in functions for reading, writing, and appending files using the open() function.

In this tutorial, you'll learn how to handle files in Python with practical examples using modes like 'r', 'w', 'a', and 'x'.

1. Opening a File in Python

You open a file using the open() function. Its syntax is:

file = open("filename.txt", "mode")

Common file modes:

• 'r' – Read (default)
• 'w' – Write (creates new file or truncates existing one)
• 'a' – Append (creates file if it doesn’t exist)
• 'x' – Create (fails if file exists)
• 'b' – Binary mode
• 't' – Text mode (default)

2. Reading from a File

# Example 1: Reading entire content
file = open("example.txt", "r")
content = file.read()
print(content)
file.close()

# Example 2: Reading line by line
file = open("example.txt", "r")
for line in file:
    print(line.strip())
file.close()

3. Writing to a File

Using 'w' mode will overwrite the file if it exists.

# Example 3: Writing to a file
file = open("data.txt", "w")
file.write("Python is powerful.\n")
file.write("File handling is easy.")
file.close()

4. Appending to a File

'a' mode adds content to the end of the file without erasing the existing data.

# Example 4: Appending to a file
file = open("data.txt", "a")
file.write("\nThis line is appended.")
file.close()

5. Using with Statement (Best Practice)

The with statement automatically closes the file, even if an error occurs.

# Example 5: Using 'with' to read
with open("data.txt", "r") as file:
    print(file.read())

# Example 6: Using 'with' to write
with open("newfile.txt", "w") as file:
    file.write("This file was created using 'with'.")

6. Reading Files into a List

# Example 7: Reading all lines into a list
with open("data.txt", "r") as file:
    lines = file.readlines()

print(lines)

7. Check if File Exists

import os

if os.path.exists("data.txt"):
    print("File exists")
else:
    print("File does not exist")

8. Deleting a File

import os

if os.path.exists("oldfile.txt"):
    os.remove("oldfile.txt")
else:
    print("The file does not exist")

9. Creating a New File (Safely)

# Example 8: Creating a new file safely
try:
    file = open("newdoc.txt", "x")
    file.write("Created a new document.")
    file.close()
except FileExistsError:
    print("File already exists.")

10. Summary Table

11. Final Thoughts

Python’s file handling is clean and beginner-friendly. By learning how to read, write, append, and delete files, you open up a whole new world of possibilities—from logging, report generation, and data storage to configuration management. Always remember to use the with statement for safer file operations.