A quirk/gotcha of for i, x in enumerate(seq) when seq is empty
Rick Johnson
rantingrickjohnson at gmail.com
Fri Feb 24 07:32:29 EST 2012
On Feb 23, 6:30 pm, Alex Willmer <a... at moreati.org.uk> wrote:
> [...]
> as a standard looping-with-index construct. In Python for loops don't
> create a scope, so the loop variables are available afterward. I've
> sometimes used this to print or return a record count e.g.
>
> for i, x in enumerate(seq):
> # do stuff
> print 'Processed %i records' % i+1
You could employ the "else clause" of "for loops" to your advantage;
(psst: which coincidentally are working pro-bono in this down
economy!)
>>> for x in []:
... print x
... else:
... print 'Empty Iterable'
Empty Iterable
>>> for i,o in enumerate([]):
... print i, o
... else:
... print 'Empty Iterable'
Empty Iterable
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