which way of checking item in list is correct

Question

which way of checking item in list is correct?

>>> lst1 = ['A', 'B']
>>> if 'C' not in lst1: print 'Hi'
...
Hi

or

>>> if not 'C' in lst1: print 'Hi'
...
Hi

to me the first one looks correct but still in doubt ? not sure if this has been asked by someone on SO before if so please link

Either one works. Subjectively I prefer `if 'c' not in lst` because I find it more human readable — Adam Smith, Feb 06 '15 at 05:35
possible duplicate of [Python \`if x is not None\` or \`if not x is None\`?](http://stackoverflow.com/questions/2710940/python-if-x-is-not-none-or-if-not-x-is-none) — Andy, Feb 06 '15 at 05:38

score 1 · Answer 1 · answered Feb 06 '15 at 06:25

1

The latter works, but some would consider it poor form or "less Pythonic". The former is more readable, and Python prides itself on being a highly readable language.

Readability counts.

— Tim Peters, The Zen of Python

answered Feb 06 '15 at 06:25

fletom

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score 0 · Accepted Answer · answered Feb 06 '15 at 05:37

0

They are equally correct for this case.

In the more general case such as when calling a function which returns a boolean, the not must go in front, so if that is easier for you to remember, you could stick with that to be consistent.

answered Feb 06 '15 at 05:37

merlin2011

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which way of checking item in list is correct

2 Answers2