Steven D'Aprano wrote: > On Wed, 15 Feb 2006 08:44:10 +0100, Marc 'BlackJack' Rintsch wrote: > >> In <[EMAIL PROTECTED]>, Farel wrote: >> >>> Which is Faster in Python and Why? >> >> ``if not b in m`` looks at each element of `m` until it finds `b` in it >> and stops then. Assuming `b` is in `m`, otherwise all elements of `m` are >> "touched". >> >> ``if m.count(b) > 0`` will always goes through all elements of `m` in the >> `count()` method. > > But the first technique executes in (relatively slow) pure Python, while > the count method executes (relatively fast) C code. So even though count > may do more work, it may do it faster.
Why does "not b in m" execute in pure Python? list.__contains__ is implemented in C code as well as list.count. Georg -- http://mail.python.org/mailman/listinfo/python-list
