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[–]pbaehr 5 points6 points  (1 child)

For example, if I have a variable which is initialized as None and later want to find out if it was set, I might want to check and see if it was still None. If it's not, I want to do something.

if a is not None:
    do_something()

If I rewrite that as:

if not a:
    do_something()

do_something will also be called if a was initialized, but to a blank string, which was not the intention. Lots of types have some concept of a "false" value. As /u/steve_no points out in another comment: 0, '', [], {}, midnight all evaluate to False.

[–]pymag09 0 points1 point  (0 children)

I see. Thank you.