Tag: Python File Processing

How Do I Open A Log File In Python?

December 15, 2022 / / 0 Comments

In my early days as a QA engineer / Python developer, I was working on test-related projects a lot. For such projects, the focus is on logging and the question: “How do I open a log file in Python?” comes up on a daily basis. Let’s look into possible solutions in this post.

How Do I Open A Log File In Python?

In Python, you can use the open() function to open a log file.

This function needs to know the file path and the mode (like ‘read’ or ‘write’) that you want to use.

In Python, the r mode is used to open a file in read mode. 

with open('log.txt', 'r') as log_file:
    content = log_file.read()

print('content: ', content)

This means that when you open a file with this mode, you can read the data from the file, but you cannot write to it.

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How Do You Change A Specific Line In A Text File In Python?

How Do You Change A Specific Line In A Text File In Python?

December 12, 2022 / / 0 Comments

I used to be a QA engineer and when I first got into Python, one of the first questions that came to my mind while working on Python scripts was: “How Do You Change A Specific Line In A Text File In Python?” We will discuss the answer to this question in much detail below. 

How Do You Change A Specific Line In A Text File In Python?

To change a specific line in a text file in Python, you can use the replace() method on strings, which allows you to specify the text you want to replace and the text you want to replace it with.

Here is a quick example:

# Open the file in read mode
with open('your_text_file_path.txt', 'r') as f:
    # Read the contents of the file into a list of lines
    lines = f.readlines()

# Use for loop to go through each line in a "your_text_file_path.txt"
for line_index, line in enumerate(lines):

    # Check each line for "old_text" and replace it
    # with "new_text" if it is found
    lines[line_index] = (
        lines[line_index]
        .replace('old_text', 'new_text')
    )

# Open a new file in writing mode (this will create a new file)
with open('your_new_text_file_path.txt', 'w') as f:
    # Write the modified lines to the new "your_new_text_file_path.txt"
    f.writelines(lines)
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