Writing to file using Python

27    Asked by JamesWilson in Python , Asked on Aug 16, 2025

How can you write data to a file in Python, and what methods or modes are available for doing so? What’s the simplest way to store text, logs, or structured content into a file using Python?

Answered by Ishii Watanabe

Writing to a file in Python is a very common task, whether you’re saving logs, configuration data, or results from your program. Python makes this process simple with its built-in open() function, which allows you to create, write, or append to files.

Here’s how you can do it step by step:

Basic Syntax:

 with open("example.txt", "w") as file:

    file.write("Hello, World!")

  • "w" → Opens the file for writing (overwrites if it already exists).
  • "a" → Opens the file for appending (adds new content without removing old content).
  • "x" → Creates a new file, but throws an error if the file already exists.

Using with Statement:

 The with block is preferred because it automatically closes the file once the block ends, even if an error occurs.

Writing Multiple Lines:

 lines = ["First line
", "Second line
", "Third line
"]

with open("example.txt", "w") as file:

    file.writelines(lines)

Binary Files:

 If you want to write non-text data (like images), you can open the file in binary mode:

 with open("image.png", "wb") as file:

    file.write(binary_data)

Key Points to Remember:

  • Always choose the correct mode (w, a, x, b) depending on your task.
  • Use the with statement to avoid leaving files open accidentally.
  • Add
    manually if you want new lines when writing text.

In short, Python makes file writing straightforward and flexible, whether you’re working with plain text or binary data.



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