Is this a "gotcha" in Python?
skip.montanaro at gmail.com
Mon Apr 22 18:20:36 EDT 2019
> Interesting. So it would flag this code?
> for _ in range(5): next(f) # skip five lines
As of at least recent versions (I have 2.1.1 in my Conda install at
home) It seems to properly accept "_" as a variable name, even when
not used. It also seems to accept any variable name as a loop index.
Here's a silly function which demonstrates current behavior:
f = open(filename)
_ = filename.lower()
_up = filename.upper()
for i in range(5):
The assignment to "_" is accepted, as is the use of "i" as the loop
variable. The assignment to _up is flagged though. It also doesn't
complain about the ignored return value for filename.title(). (In all
fairness, I don't think pyflakes was ever held up as a "deep" analyzer
of Python source, so couldn't be expected to know that string's title
method operates without side effect.)
So, it's improving.
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