Raymond Hettinger <[EMAIL PROTECTED]> writes:
> Good question. To see the answer, look at a code tranformation from:
>
> if file_ext.lower() in set(['html', 'xml', 'xhtml']):
> handle(filename)
>
> into:
>
>
> if file_ext.lower() in {'html', 'xml', 'xhtml'}:
> handle(filename)
Beware that without optimization this:
if file_ext.lower() in ['html', 'xml', 'xhtml']:
handle(filename)
is probably faster than this:
if file_ext.lower() in {'html', 'xml', 'xhtml'}:
handle(filename)
and with some trivial optimization this:
if file_ext.lower() in ('html', 'xml', 'xhtml'):
handle(filename)
is even faster (the tuple can be allocated statically).
So from the efficiency point of view using sets in such cases is a loss.
And I'm not sure that optimizing 'x in {a,b,c}' to comparisons would be
justified: it gives different results if some of a,b,c are not hashable.
--
__("< Marcin Kowalczyk
\__/ [EMAIL PROTECTED]
^^ http://qrnik.knm.org.pl/~qrczak/
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