How do I make multi-line comments? Most languages have block comment symbols like:
/*
*/
How do I make multi-line comments? Most languages have block comment symbols like:
/*
*/
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, like this:
# This is a multiline
# comment.
...and this is also what you'll find in many projects. Text editors usually have a shortcut to do this easily.
test.py
just to see. When I do import test
, a test.pyc
file is generated. Unfortunately, the pyc
file is huge and contains the entire string as plain text. Am I misunderstanding something, or is this tweet incorrect? –
Ln pyc
. I edited the answer and put „module“ to the list of things that have docstrings. –
Myrnamyrobalan """
for docstrings and '''
for block comments. In this manner you can wrap '''
around your usual docstrings without conflict. –
Buckwheat '''
when I only want a small comment in a line of code. –
Disenfranchise #
lines to distinguish paragraphs. –
Instantly "\N{BLACK STAR}"
in Python 3). It does the same thing in Python 2 Unicode strings as well. You'll have the same problem with \x
, \u
, and \U
. –
Myrnamyrobalan Indentation Error...
which I finally figured out was due to there being a triple-quoted '''comment''' right before an elif
statement. Since the '''string-literal''' is actually just code that does nothing (not a comment) it does affect indentations. –
Cormier '''
to multi-line comment is terrible procedure as it is not ignored by the interpreter like an actual comment is. It is garbage-collected instantly, but the code is still using resources. –
Kathie /* */
. –
Jaleesa '''block comment'''
instead of pass
. I find this helpful to explain an empty except-clause or if-else-clause. –
Ersatz #
before the closing '''
. Now, if you put another #
before the opening '''
, the whole section will be code. If you remove the first #
again, it will be back to multiline string. Really helpful to temporarily disable several/lots of lines of code easily (unless they contain '''
multiline strings, of course). But then again, you could use double-quotes for your toggle. –
Compelling indentation error
. I did indent the apostrophes correctly. Could you please help me out? is it necessary to indent the apostrophes just like the previous line? Or can I start it from the start of the new physical line? –
Australorp Pep8
recommending multi-line strings is yet another big fail on that spec. It's one of the worst things for a language already having major issues. In an age of 3K laptops: 79-character lines (which much of that taken up by the 4-space indentations) anyone?? –
Helen PEP8
that are not aware of that option to use the 99 length. –
Helen 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! :-)
return
command above it. –
Xenon 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()
r'raw string'
-- r'\xor' == '\\xor'
. –
Via */
as it will terminate the block, for example. –
Surbased '''
"comments" have more limitations. You can only comment out whole statements, whereas comments can comment out parts of expression. Example: In C, you can comment out some list elements: int a[] = {1, 2, /* 3, 4, */ 5};
. With Multi line string, you can't do that, as that would put a string inside your list. –
Raouf 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
"""
weather2
comment is actually a docstring since it's the first thing in the class. –
Chaperone 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.
There is no such feature as a multi-line comment. #
is the only way to comment a single line of code.
Many of you answered ''' a comment ''' this as their solution.
It seems to work, but internally '''
in Python takes the lines enclosed as a regular strings which the interpreter does not ignores like comment using #
.
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.
If you put a comment in
"""
long comment here
"""
in the middle of a script, Python/linters won't recognize that. Folding will be messed up, as the above comment is not part of the standard recommendations. It's better to use
# Long comment
# here.
If you use Vim, you can plugins like commentary.vim, to automatically comment out long lines of comments by pressing Vjgcc
. Where Vj
selects two lines of code, and gcc
comments them out.
If you don’t want to use plugins like the above you can use search and replace like
:.,.+1s/^/# /g
This will replace the first character on the current and next line with #
.
Visual Studio Code universal official multi-line comment toggle. Similar to Xcode shortcut.
macOS: Select code-block and then ⌘+/
Windows: Select code-block and then Ctrl+/
Unfortunately stringification can not always be used as commenting out! So it is safer to stick to the standard prepending each line with a #
.
Here is an example:
test1 = [1, 2, 3, 4,] # test1 contains 4 integers
test2 = [1, 2, '''3, 4,'''] # test2 contains 2 integers **and the string** '3, 4,'
I would advise against using """
for multi line comments!
Here is a simple example to highlight what might be considered an unexpected behavior:
print('{}\n{}'.format(
'I am a string',
"""
Some people consider me a
multi-line comment, but
"""
'clearly I am also a string'
)
)
Now have a look at the output:
I am a string
Some people consider me a
multi-line comment, but
clearly I am also a string
The multi line string was not treated as comment, but it was concatenated with 'clearly I'm also a string'
to form a single string.
If you want to comment multiple lines do so according to PEP 8 guidelines:
print('{}\n{}'.format(
'I am a string',
# Some people consider me a
# multi-line comment, but
'clearly I am also a string'
)
)
Output:
I am a string
clearly I am also a string
Well, you can try this (when running the quoted, the input to the first question should quoted with '
):
"""
print("What's your name? ")
myName = input()
print("It's nice to meet you " + myName)
print("Number of characters is ")
print(len(myName))
age = input("What's your age? ")
print("You will be " + str(int(age)+1) + " next year.")
"""
a = input()
print(a)
print(a*5)
Whatever enclosed between """
will be commented.
If you are looking for single-line comments then it's #
.
Multiline comment in Python:
For me, both ''' and """ worked.
Example:
a = 10
b = 20
c = a+b
'''
print ('hello')
'''
print ('Addition is: ', a+b)
Example:
a = 10
b = 20
c = a+b
"""
print('hello')
"""
print('Addition is: ', a+b)
If you write a comment in a line with a code, you must write a comment, leaving 2 spaces before the # sign and 1 space before the # sign
print("Hello World") # printing
If you write a comment on a new line, you must write a comment, leaving 1 space kn in the # sign
# single line comment
To write comments longer than 1 line, you use 3 quotes
"""
This is a comment
written in
more than just one line
"""
On Python 2.7.13:
Single:
"A sample single line comment "
Multiline:
"""
A sample
multiline comment
on PyCharm
"""
The inline comments in Python starts with a hash character.
hello = "Hello!" # This is an inline comment
print(hello)
Hello!
Note that a hash character within a string literal is just a hash character.
dial = "Dial #100 to make an emergency call."
print(dial)
Dial #100 to make an emergency call.
A hash character can also be used for single or multiple lines comments.
hello = "Hello"
world = "World"
# First print hello
# And print world
print(hello)
print(world)
Hello
World
Enclose the text with triple double quotes to support docstring.
def say_hello(name):
"""
This is docstring comment and
it's support multi line.
:param name it's your name
:type name str
"""
return "Hello " + name + '!'
print(say_hello("John"))
Hello John!
Enclose the text with triple single quotes for block comments.
'''
I don't care the parameters and
docstrings here.
'''
Using PyCharm IDE.
You can
comment
anduncomment
lines of code using Ctrl+/. Ctrl+/ comments or uncomments the current line or several selected lines with single line comments({# in Django templates, or # in Python scripts)
.Pressing Ctrl+Shift+/
for a selected block of source code in a Django template surrounds the block with{% comment %} and {% endcomment %}
tags.
n = 5
while n > 0:
n -= 1
if n == 2:
break
print(n)
print("Loop ended.")
Select all lines then press Ctrl + /
# n = 5
# while n > 0:
# n -= 1
# if n == 2:
# break
# print(n)
# print("Loop ended.")
Yes, it is fine to use both:
'''
Comments
'''
and
"""
Comments
"""
But, the only thing you all need to remember while running in an IDE, is you have to 'RUN' the entire file to be accepted as multiple lines codes. Line by line 'RUN' won't work properly and will show an error.
Among other answers, I find the easiest way is to use the IDE comment functions which use the Python comment support of #
.
I am using Anaconda Spyder and it has:
It would comment/uncomment a single/multi line/s of code with #
.
I find it the easiest.
For example, a block comment:
# =============================================================================
# Sample Commented code in spyder
# Hello, World!
# =============================================================================
Yes, you can simply use
'''
Multiline!
(?)
'''
or
"""
Hello
World!
"""
BONUS: It's a little bit harder, but it's safer to use in older versions, print
functions or GUIs:
# This is also
# a multiline comment.
For this one, you can select the text you want to comment and press Ctrl
/
(or ⌘
/
), in PyCharm and VS Code.
But you can edit them. For example, you can change the shortcut from Ctrl
/
to Ctrl
Shift
C
.
WARNING!
Hope this answer helped. Good luck next time when you'll write other answers!
This can be done in Vim text editor.
Go to the beginning of the first line in the comment area.
Press Ctrl+V to enter the visual mode.
Use arrow keys to select all the lines to be commented.
Press Shift+I.
Press # (or Shift+3).
Press Esc.
A multiline comment doesn't actually exist in Python. The below example consists of an unassigned string, which is validated by Python for syntactical errors.
A few text editors, like Notepad++, provide us shortcuts to comment out a written piece of code or words.
def foo():
"This is a doc string."
# A single line comment
"""
This
is a multiline
comment/String
"""
"""
print "This is a sample foo function"
print "This function has no arguments"
"""
return True
Also, Ctrl + K is a shortcut in Notepad++ to block comment. It adds a #
in front of every line under the selection. Ctrl + Shift + K is for block uncomment.
Select the lines that you want to comment and then use Ctrl + ? to comment or uncomment the Python code in the Sublime Text editor.
For single line you can use Shift + #.
For commenting out multiple lines of code in Python is to simply use a #
single-line comment on every line:
# This is comment 1
# This is comment 2
# This is comment 3
For writing “proper” multi-line comments in Python is to use multi-line strings with the """
syntax
Python has the documentation strings (or docstrings) feature. It gives programmers an easy way of adding quick notes with every Python module, function, class, and method.
'''
This is
multiline
comment
'''
Also, mention that you can access docstring by a class object like this
myobj.__doc__
You can use the following. This is called DockString.
def my_function(arg1):
"""
Summary line.
Extended description of function.
Parameters:
arg1 (int): Description of arg1
Returns:
int: Description of return value
"""
return arg1
print my_function.__doc__
in windows: you can also select the text or code chunks and press ctr + /
and do the same if you want to remove the comments.
in mac: it should be comment + /
I read about all of the drawbacks of the various ways of doing this, and I came up with this way, in an attempt to check all the boxes:
block_comment_style = '#[]#'
'''#[
class ExampleEventSource():
def __init__(self):
# create the event object inside raising class
self.on_thing_happening = Event()
def doing_something(self):
# raise the event inside the raising class
self.on_thing_happening()
class ExampleEventHandlingClass():
def __init__(self):
self.event_generating_thing = ExampleEventSource()
# add event handler in consuming class
event_generating_thing.on_thing_happening += my_event_handler
def my_event_handler(self):
print('handle the event')
]#'''
class Event():
def __init__(self):
self.__eventhandlers = []
def __iadd__(self, handler):
self.__eventhandlers.append(handler)
return self
def __isub__(self, handler):
self.__eventhandlers.remove(handler)
return self
def __call__(self, *args, **keywargs):
for eventhandler in self.__eventhandlers:
eventhandler(*args, **keywargs)
Pros
help()
pyc
. (Except the one line of code that enables pros #1 and #4)'''
doesn't have this advantage.Cons
Pylint
might complain about it. I don't know. Maybe; maybe not.Here's an attempt at the VS Code macro, although I haven't tested it yet:
{
"key": "ctrl+shift+/",
"command": "editor.action.insertSnippet",
"when": "editorHasSelection"
"args": {
"snippet": "block_comment_style = '#[]#'\n'''#[{TM_SELECTED_TEXT}]#'''"
}
}
comment
–
Philistine © 2022 - 2024 — McMap. All rights reserved.
#
is the only way to make comments. I'm guessing that it makes it easier to interpret Python scripts this way. – Assignee