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How to check if a string is empty in python?

Dustan DustanGroups at gmail.com
Thu May 3 07:07:27 EDT 2007 
On May 2, 5:50 pm, Steven D'Aprano
<s... at REMOVE.THIS.cybersource.com.au> wrote:
> On Wed, 02 May 2007 13:35:47 -0700, noagbodjivictor wrote:
> > How to check if a string is empty in python?
> > if(s == "") ??
>
> In no particular order, all of these methods will work:
>
> # test s is equal to another empty string
> if s == "":
>
> # assuming s is a string, test that it is empty
> if not s:
>
> # test s is a string and it is empty
> if isinstance(s, str) and not s:
>
> # test s has length 0
> if len(s) == 0:
>
> # test the length of s evaluates as false
> if not len(s):
>
> # a long way to test the length of s
> if s.__len__() < 1:
>
> # a stupid way to test s is empty
> if bool(s) == False:
>
> # a REALLY stupid way to test s is empty
> if (bool(s) == False) == True:
>
> # test that appending s to itself is itself
> if s+s == s:

Being the slow person that I am, it really did take me this long to
find a mistake.
s+s != 'appending'
s+s == 'concatenation'

> # test that s has none of any character
> if not filter(None, [1 + s.find(chr(n)) for n in range(256)]):
>
> That last one is really only good for wasting CPU cycles.
>
> --
> Steven.
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