How to check if a string is empty in python?

[mensanator at aol.com]

On May 4, 1:31 pm, "Hamilton, William " <wham... at entergy.com> wrote:
> > -----Original Message-----
> > From: mensana... at aol.com
>
> > On May 4, 5:02 am, Jaswant <mailme.gurpr... at gmail.com> wrote:
> > > This is  a simple way to do it i think
>
> > > s=hello
>
> > > >>> if(len(s)==0):
>
> > > ...     print "Empty"
> > > ... else:
> > > ...     print s
> > > ...
> > > hello
>
> > But you are still making the assumption that s is a string.
> > (BTW, you need quotes around your example.)
>
> > For example:
>
> > >>> print a,b
> > 11 11
>
> > Can you tell which one is the string? I.e., which one had quotes
> > around it?
>
> > If you correctly assume that it was b, then yes, your example works.
>
> > >>> print len(b)
> > 2
>
> > If you incorrectly assume it was a, then the example doesn't work.
>
> > >>> print len(a)
> > Traceback (most recent call last):
> >   File "<pyshell#8>", line 1, in <module>
> >     print len(a)
> > TypeError: object of type 'int' has no len()
>
> > You have to know that a variable is a string before you try to do a
> > len().
>
> > Dynamic typing is a feature, but that doesn't relieve you of the
> > necessary tests.
>
> Your point would be important if the question were "How can I tell if x
> is an empty string?"  On the other hand, "How to check if a string is
> empty?" implies that the OP already knows it is a string.  Maybe he's
> been using string methods on it, maybe he got it from a function that he
> knows provides a string. Maybe he's checked its type.  It doesn't really
> matter, if he's aware it is a string he doesn't have to test it for
> stringness.

OTOH, some don't know enough to quote their string literals, so I
think
my point is well justified.

>
> ---
> -Bill Hamilton