Related
I am struggling with multi line comments in Python, I understood I can use # at the start of every line of multi line comments but there is also another way of using """ at the start and end of the comment; however, in my interpreter the """ method gives an output instead of ignoring the comment.
>>> """this should
be a multi
line comment"""
And my interpreter gives the following output:
'this should\nbe a multi\nline comment'
Can someone explain it?
Triple quoted strings are used as comments by many developers but it is actually not a comment. It is similar to regular strings in python but it allows the string to be multi-line. You will find no official reference for triple quoted strings to be a comment.
In python, there is only one type of comment that starts with hash # and can contain only a single line of text.
According to PEP 257, it can however be used as a docstring, which is again not really a comment.
def foo():
"""
Developer friendly text for describing the purpose of function
Some test cases used by different unit testing libraries
"""
<body of the function>
You can just assign them to a variable as you do with single quoted strings:
x = """a multi-line text
enclosed by
triple quotes
"""
Furthermore, if you try it in a repl, triple quoted strings get printed, had it really been a comment, should it have been printed?:
>>> #comment
>>> """triple quoted"""
'triple quoted'
This is very easy to accomplish in python.
# This is a single-line comment
'''
This is a multi-line comment
'''
Just put the comments in ''' and put whatever you want inside of them!
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.
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! :-)
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()
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
"""
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 #.
Check the official documentation here
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 and uncomment 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:
Ctrl + 1 - Comment/uncomment
Ctrl + 4 - Comment a block of code
Ctrl + 5 - Uncomment a block of code
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!
Be careful, don't overwrite other shortcuts!
Comments have to be correctly indented!
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.
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__
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 + #.
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
It is obvious to any other programmer this is a comment. It's self-descriptive.
It compiles
It doesn't show up as a doc comment in help()
It can be at the top of the module if desired
It can be automated with a macro.
[The comment] is not part of the code. It doesn't end up in the pyc. (Except the one line of code that enables pros #1 and #4)
If multi-line comment syntax was ever added to Python, the code files could be fixed with find and replace. Simply using ''' doesn't have this advantage.
Cons
It's hard to remember. It's a lot of typing. This con can be eliminated with a macro.
It might confuse newbies into thinking this is the only way to do block comments. That can be a pro, just depends on your perspective. It might make newbies think the line of code is magically connected to the comment "working".
It doesn't colorize as a comment. But then again, none of the answers that actually address the spirit of the OP's question would.
It's not the official way, so 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}]#'''"
}
}
This question already has answers here:
Python comments: # vs. strings
(3 answers)
Closed 6 years ago.
I am still exploring python. Today I came across multi-line strings. If I do:
a = '''
some-text
'''
The content of variable a is '\nsome-text\n'. But this leaves me confused. I always thought that if you enclose something within three single quotes ('''), you are commenting it out. So the above statement would be equivalent to something like this in C++:
a = /*
some-text
*/
What am I missing?
Technically such multi-line-comments enclosed in triple quotes are not really comments but string literals.
The reason why you can still use them to comment stuff out is that a string literal itself does not represent any kind of operation. It gets parsed, but nothing is done with it and it does not get assigned to a variable name, so it gets ignored.
You could also place any other literal into your code. As long as it is not involved in any kind of operation or assignment, it gets basically ignored like a comment. It is not a comment though, just useless code if you want to name it that way.
Here's an example of code that does... well, nothing:
# This is a real comment.
"useless normal string"
"""useless triple-quoted
multi-line
string"""
[1, "two"] # <-- useless list
42 # <-- useless number
I always thought that if you enclose something within three single quotes (''')
This is not the case, actually. Enclosing something in triple quotes '''string''', it creates a string expression which yields a string containing the characters within the quotes. The difference between this and a single quoted string 'string' is that the former can be on multiple lines. People often use this to comment out multiple lines.
However, if you don't assign the string expression to a variable, then you'll get something a lot like a comment.
'''this is
a useless piece of python
text that does nothing for
your program'''
In python, wrapping your code with ''' will encode it as a string, effectively commenting it out unless that code already contains a multi-line string literal ''' anywhere. Then, the string will be terminated.
print('''hello!
How are you?''')
# this will not have the intended comment effect
'''
print('''hello!
How are you?''')
'''
I can't find any PEP reference to this detail. There has to be a blank line after function definition?
Should I do this:
def hello_function():
return 'hello'
or shoud I do this:
def hello_function():
return 'hello'
The same question applies when docstrings are used:
this:
def hello_function():
"""
Important function
"""
return 'hello'
or this
def hello_function():
"""
Important function
"""
return 'hello'
EDIT
This is what the PEP says on the blank lines, as commented by FoxMaSk, but it does not say anything on this detail.
Blank Lines
Separate top-level function and class definitions with two blank
lines.
Method definitions inside a class are separated by a single blank
line.
Extra blank lines may be used (sparingly) to separate groups of
related functions. Blank lines may be omitted between a bunch of
related one-liners (e.g. a set of dummy implementations).
Use blank lines in functions, sparingly, to indicate logical sections.
Python accepts the control-L (i.e. ^L) form feed character as
whitespace; Many tools treat these characters as page separators, so
you may use them to separate pages of related sections of your file.
Note, some editors and web-based code viewers may not recognize
control-L as a form feed and will show another glyph in its place.
Read Docstring Conventions.
It says that even if the function is really obvious you have to write a one-line docstring. And it says that:
There's no blank line either before or after the docstring.
So I would code something like
def hello_function():
"""Return 'hello' string."""
return 'hello'
As pointed out by #moliware, the Docstring Conventions state, under One-line Docstrings:
There's no blank line either before or after the docstring.
HOWEVER, it also says (under Multi-line Docstrings):
Insert a blank line after all docstrings (one-line or multi-line) that document a class -- generally speaking, the class's methods are separated from each other by a single blank line, and the docstring needs to be offset from the first method by a blank line.
My interpretation of all this: blank lines should never precede any docstring, and should only follow a docstring when it is for a class.
Projects use different docstring conventions.
For example, the pandas docstring guide explicitly requires you to put triple quotes into a line of their own.
Docstrings must be defined with three double-quotes. No blank lines should be left before or after the docstring. The text starts in the next line after the opening quotes. The closing quotes have their own line (meaning that they are not at the end of the last sentence).
Making a python script simultaneously adhere to pydocstyle and pycodestyle is a challenge. But one thing which greatly helps is that in your docstring write the first line as summary of the function or class within 79 characters including ..This way you adhere to both PEP 257 (as per pydocstyle) of having a period at the end of an unbroken line and 79 characters limit of PEP 8 (as per pycodestyle).
Then after leaving one blank line (for that using new line shortcut of your coditor is better than manually pressing enter) you can write whatever you want and at that time focusing only on pycodestyle which is slightly easier than pydocstyle and the main reason is that our understanding of line and indentation is quite different than what system understands due to indentation settings, tab settings, line settings in the various code editors we use.So in this way you will have TODO from pycodestyle which you understand and can rectify instead of banging your head against the wall on pydocstyle TODOs.
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.
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! :-)
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()
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
"""
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 #.
Check the official documentation here
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 and uncomment 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:
Ctrl + 1 - Comment/uncomment
Ctrl + 4 - Comment a block of code
Ctrl + 5 - Uncomment a block of code
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!
Be careful, don't overwrite other shortcuts!
Comments have to be correctly indented!
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.
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__
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 + #.
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
It is obvious to any other programmer this is a comment. It's self-descriptive.
It compiles
It doesn't show up as a doc comment in help()
It can be at the top of the module if desired
It can be automated with a macro.
[The comment] is not part of the code. It doesn't end up in the pyc. (Except the one line of code that enables pros #1 and #4)
If multi-line comment syntax was ever added to Python, the code files could be fixed with find and replace. Simply using ''' doesn't have this advantage.
Cons
It's hard to remember. It's a lot of typing. This con can be eliminated with a macro.
It might confuse newbies into thinking this is the only way to do block comments. That can be a pro, just depends on your perspective. It might make newbies think the line of code is magically connected to the comment "working".
It doesn't colorize as a comment. But then again, none of the answers that actually address the spirit of the OP's question would.
It's not the official way, so 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}]#'''"
}
}