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Is there a way to create multiline comments in Python?


Question

I have recently started studying Python, but I couldn't find how to implement multi-line comments. Most languages have block comment symbols like

/*

*/

I tried this in Python, but it throws an error, so this probably is not the correct way. Does Python actually have a multiline comment feature?

2020/02/05
1
1173
2/5/2020 8:43:51 PM

Accepted Answer

You can use triple-quoted strings. When they're not a docstring (the first thing in a class/function/module), they are ignored.

'''
This is a multiline
comment.
'''

(Make sure to indent the leading ''' appropriately to avoid an IndentationError.)

Guido van Rossum (creator of Python) tweeted this as a "pro tip".

However, Python's style guide, PEP8, favors using consecutive single-line comments, and this is also what you'll find in many projects. Text editors usually have a shortcut to do this easily.

2020/02/03
1832
2/3/2020 4:56:45 PM

Python does have a multiline string/comment syntax in the sense that unless used as docstrings, multiline strings generate no bytecode -- just like #-prepended comments. In effect, it acts exactly like a comment.

On the other hand, if you say this behavior must be documented in the official documentation to be a true comment syntax, then yes, you would be right to say it is not guaranteed as part of the language specification.

In any case, your text editor should also be able to easily comment-out a selected region (by placing a # in front of each line individually). If not, switch to a text editor that does.

Programming in Python without certain text editing features can be a painful experience. Finding the right editor (and knowing how to use it) can make a big difference in how the Python programming experience is perceived.

Not only should the text editor be able to comment-out selected regions, it should also be able to shift blocks of code to the left and right easily, and it should automatically place the cursor at the current indentation level when you press Enter. Code folding can also be useful.


To protect against link decay, here is the content of Guido van Rossum's tweet:

@BSUCSClub Python tip: You can use multi-line strings as multi-line comments. Unless used as docstrings, they generate no code! :-)

2020/02/03

From the accepted answer...

You can use triple-quoted strings. When they're not a docstring (first thing in a class/function/module), they are ignored.

This is simply not true. Unlike comments, triple-quoted strings are still parsed and must be syntactically valid, regardless of where they appear in the source code.

If you try to run this code...

def parse_token(token):
    """
    This function parses a token.
    TODO: write a decent docstring :-)
    """

    if token == '\\and':
        do_something()

    elif token == '\\or':
        do_something_else()

    elif token == '\\xor':
        '''
        Note that we still need to provide support for the deprecated
        token \xor. Hopefully we can drop support in libfoo 2.0.
        '''
        do_a_different_thing()

    else:
        raise ValueError

You'll get either...

ValueError: invalid \x escape

...on Python 2.x or...

SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 79-80: truncated \xXX escape

...on Python 3.x.

The only way to do multi-line comments which are ignored by the parser is...

elif token == '\\xor':
    # Note that we still need to provide support for the deprecated
    # token \xor. Hopefully we can drop support in libfoo 2.0.
    do_a_different_thing()
2016/06/29

In Python 2.7 the multiline comment is:

"""
This is a
multilline comment
"""

In case you are inside a class you should tab it properly.

For example:

class weather2():
   """
   def getStatus_code(self, url):
       world.url = url
       result = requests.get(url)
       return result.status_code
   """
2019/07/29

AFAIK, Python doesn't have block comments. For commenting individual lines, you can use the # character.

If you are using Notepad++, there is a shortcut for block commenting. I'm sure others like gVim and Emacs have similar features.

2017/05/23

I think it doesn't, except that a multiline string isn't processed. However, most, if not all Python IDEs have a shortkey for 'commenting out' multiple lines of code.

2014/03/23

Source: https://stackoverflow.com/questions/7696924
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