Commenting out multiple lines in Python is a basic skill that helps you temporarily disable a block of code, leave notes for yourself, or test an alternative version of the logic without deleting anything.
The simplest method: add # to each line
The most reliable way to comment out multiple lines in Python is to put a # at the start of every line you want to disable.
This approach works in any Python code and does not depend on the interpreter version.
- Before: active code that runs.
- After: lines with # that Python ignores.
Example:
- # print("First line")
- # print("Second line")
- # print("Third line")
The check is simple: after you run the program, these lines should not appear in the output. If the code still runs, at least one line is missing a #.
Why triple quotes are not the best choice
Triple quotes ”’ or """ are sometimes used as a pseudo-comment for multiple lines, but they are not real comments in Python.
That block creates a string literal. If it is not attached to a variable or used as documentation, the interpreter usually skips it, but the behavior is less clear than with regular comments.
For temporarily disabling code, # on each line is the better option. Triple quotes are more appropriate for docstrings than for hiding working logic.
How to comment out multiple lines quickly in an editor
Most code editors let you comment out multiple lines with a single keyboard shortcut.
That is faster than adding # manually, especially when you are working with a large block of code.
- Select the lines you need.
- Use the editor’s comment shortcut.
- Check that # appeared at the start of each line.
- Run the code and confirm that the block no longer executes.
If the shortcut does not work, the usual causes are the wrong keyboard layout, a different shortcut profile, or editor-specific differences.
When to comment code and when to delete it
You should comment out multiple lines in Python when you are temporarily disabling part of a program, comparing two versions, or leaving an explanation for yourself or your team.
You should delete code when a fragment is no longer needed. Old commented-out blocks quickly turn into clutter and make maintenance harder.
A safer approach is to comment out the block first, verify that the program still works without it, and only then remove the extra code if the fragment is truly unnecessary.
A practical rule for readable Python code
Comments in Python should explain intent, not repeat what the code already says.
If you need to turn the same block on and off often, it is usually better to move it into a separate function instead of leaving a large section commented out for a long time.
For quick edits and tests, the best rule is simple: every line that should be disabled gets its own #, and the code is checked immediately by running it.
