[issue2672] speed of set.update(

John Arbash Meinel <[EMAIL PROTECTED]> added the comment: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Raymond Hettinger wrote: > Raymond Hettinger <[EMAIL PROTECTED]> added the comment: > > John, when y=[], the update method has to create a new list iterator on > each invocation. But when y

[issue2672] speed of set.update(

Raymond Hettinger <[EMAIL PROTECTED]> added the comment: John, when y=[], the update method has to create a new list iterator on each invocation. But when y is a genexp, it is self-iterable (iow, iter (y) will return self, not a new object). Also, when doing timings, it can be helpful to facto

[issue2672] speed of set.update(

Alexander Belopolsky <[EMAIL PROTECTED]> added the comment: On Thu, Apr 24, 2008 at 2:23 PM, John Arbash Meinel <[EMAIL PROTECTED]> wrote: .. > So if you compare consuming a generator multiple times to creating it > each time, it is 0.662 usec - 0.173 usec = 0.489 usec to create a generator. >

[issue2672] speed of set.update(

John Arbash Meinel <[EMAIL PROTECTED]> added the comment: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Alexander Belopolsky wrote: > Alexander Belopolsky <[EMAIL PROTECTED]> added the comment: > > This has nothing to do with set.update, the difference is due to the > time to setup the generato

[issue2672] speed of set.update([])

Raymond Hettinger <[EMAIL PROTECTED]> added the comment: I concur. The source code for set_update() in Objects/setobject.c shows that both versions are accessed through the iterator protocol, so what you're seeing are the basic performance differences (start-up and per-item costs) for genexps

[issue2672] speed of set.update([])

Alexander Belopolsky <[EMAIL PROTECTED]> added the comment: This has nothing to do with set.update, the difference is due to the time to setup the generator: $ python -m timeit -s 'x = set(range(1)); y = []' 'x.update(y)' 100 loops, best of 3: 0.38 usec per loop $ python -m timeit -s 'x

[issue2672] speed of set.update([])

Changes by Raymond Hettinger <[EMAIL PROTECTED]>: -- assignee: -> rhettinger nosy: +rhettinger __ Tracker <[EMAIL PROTECTED]> __ ___ Python-bug

[issue2672] speed of set.update([])

Changes by John Arbash Meinel <[EMAIL PROTECTED]>: -- type: -> performance __ Tracker <[EMAIL PROTECTED]> __ ___ Python-bugs-list mailing list

[issue2672] speed of set.update([])

New submission from John Arbash Meinel <[EMAIL PROTECTED]>: I was performance profiling some of my own code, and I ran into something unexpected. Specifically, set.update(empty_generator_expression) was significantly slower than set.update(empty_list_expression). I double checked my findings wit