Do python single line comments have to obey indentation/whitespace rules?
Question:
If I have python code that requires indenting (for, with, function, etc), will a single line comment end potentially the context of the construct if I place it incorrectly? For example, presuming step1, step2 and step3 are functions already defined, will:
def myFunc():
step1()
# step2()
step3()
(unintentionally) reduce the scope of myFunc() so that it only contains step1? If I only want to remove step2 from the 3-step sequence, must I place the # at the same level of indentation as the statements within the scope of the construct? All the code I have seen so far suggests this is a requirement, but it might just be a coding habit.
Answers:
Try it out:
def myFunc():
print(1)
# print(2)
print(3)
myFunc()
which outputs:
1
3
So yeah, the answer is “Line comments don’t need to match indentation”. That said, PEP8 really prefers that they do, just for readability.
Syntax-wise, blank lines are ignored. Blank lines include lines that have any amount of white space followed by a comment.
https://docs.python.org/2/reference/lexical_analysis.html#blank-lines
Indenting a comment the way you show in your example does not change the block of code included in your function.
Convention-wise, PEP8 calls for comments indented to the same indentation as code.
It doesn’t really matter where you place the #
Either in the first identation level or close to the instruction, everything underneath it is going to be executed.
I suggest you to play with the code below and You’ll figure it out yourself.
a = 1
b = 10
c = 100
d = 1000
if (a == 1):
result = a+b
# result = result + c
result = result + d
print(result)
Python clearly considers comments when checking for indentation errors, which I hope the devs think of as a bug, and fix. I was just running a program that failed to errors, but suddently worked when I deleted some of the comments (and changed nothing else).
If I have python code that requires indenting (for, with, function, etc), will a single line comment end potentially the context of the construct if I place it incorrectly? For example, presuming step1, step2 and step3 are functions already defined, will:
def myFunc():
step1()
# step2()
step3()
(unintentionally) reduce the scope of myFunc() so that it only contains step1? If I only want to remove step2 from the 3-step sequence, must I place the # at the same level of indentation as the statements within the scope of the construct? All the code I have seen so far suggests this is a requirement, but it might just be a coding habit.
Try it out:
def myFunc():
print(1)
# print(2)
print(3)
myFunc()
which outputs:
1
3
So yeah, the answer is “Line comments don’t need to match indentation”. That said, PEP8 really prefers that they do, just for readability.
Syntax-wise, blank lines are ignored. Blank lines include lines that have any amount of white space followed by a comment.
https://docs.python.org/2/reference/lexical_analysis.html#blank-lines
Indenting a comment the way you show in your example does not change the block of code included in your function.
Convention-wise, PEP8 calls for comments indented to the same indentation as code.
It doesn’t really matter where you place the #
Either in the first identation level or close to the instruction, everything underneath it is going to be executed.
I suggest you to play with the code below and You’ll figure it out yourself.
a = 1
b = 10
c = 100
d = 1000
if (a == 1):
result = a+b
# result = result + c
result = result + d
print(result)
Python clearly considers comments when checking for indentation errors, which I hope the devs think of as a bug, and fix. I was just running a program that failed to errors, but suddently worked when I deleted some of the comments (and changed nothing else).