File Handling

What You’ll Learn

You’ll learn how to open, read, and write files using Python.

The open() Function

The key function for working with files in Python is the open() function. It takes two parameters: filename and mode.

Modes:

• "r" - Read (Default)
• "a" - Append (Adds to the end of the file)
• "w" - Write (Overwrites the file)

Reading a File

# Assuming we have a file "demo.txt"
f = open("demo.txt", "r")
print(f.read())
f.close() # Always close your files!

The with Statement (Best Practice)

It is good practice to use the with keyword when dealing with file objects. This has the advantage that the file is properly closed automatically, even if an exception is raised!

with open("demo.txt", "r") as f:
    content = f.read()
    print(content)
# No need to call f.close(), it's done automatically

Writing to a File

with open("demo.txt", "w") as f:
    f.write("Woops! I have deleted the content and added this instead!")