File Reading and Writing (Text Files)

Python allows you to read from and write to text files using the built-in open() function.

This is useful when you want to save data to a file or load data from one.

Use open(filename, mode) to access a file.

• "r" = read (default)
• "w" = write (overwrites file)
• "a" = append (adds to the end)
• "x" = create (fails if file exists)

Always close the file after using it, or use a with block.

Copy
with open("greeting.txt", "r") as file:
    content = file.read()
    print(content)

Explanation:

• with ensures the file closes automatically.
• file.read() reads the entire file content as a string.

Copy
with open("note.txt", "w") as file:
    file.write("This is a new line.")

Explanation:

• "w" mode creates the file or overwrites it.
• Use file.write() to add content.

Copy
with open("note.txt", "a") as file:
    file.write("\nThis line is added.")

Explanation:

• "a" mode adds new content without deleting existing data.

Next, you’ll learn how to work with CSV files, which are commonly used to store structured data like spreadsheets.