Modifying each line in a text file in Python

Sometimes, you may need to modify the content of a text file line by line in Python. This can be useful for tasks like finding and replacing text, adding or removing specific data, or performing other custom operations on the file. In this tutorial, we'll walk you through the process of modifying each line in a text file using Python, including code examples.
Before you begin, make sure you have Python installed on your system. You'll also need a text file that you want to modify.
Open the Text File: You need to open the text file in the appropriate mode (read or write) using the open() function.
Read the File Line by Line: Read the content of the file line by line using a loop. You can use a for loop to iterate through the lines.
Modify Each Line: Inside the loop, perform your desired modifications to each line of the file.
Write the Modified Line to a New File or Overwrite the Original File: Depending on your use case, you can either write the modified lines to a new file or overwrite the original file with the changes.
Close the Files: Always remember to close the files when you are done.
Let's say you have a text file named "input.txt" with the following content:
Now, you want to modify this file to capitalize every line. Here's a Python script to do that:
This code reads each line from "input.txt," capitalizes it, and then writes the modified lines to "output.txt." After running this script, the "output.txt" file will contain:
You can modify the modified_line assignment to apply different transformations as per your requirements.
Modifying each line in a text file in Python is a common task, and it can be accomplished with the steps outlined in this tutorial. You can adapt the example code to perform various operations on the file, such as find and replace, filtering specific lines, or any other text-based manipulation. Remember to handle file I/O errors and exceptions for robust code.
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