On Sun, 16 Oct 2005 15:52:54 +0200, Fredrik Lundh wrote: > [EMAIL PROTECTED] wrote: > >> I initially thought that generator/generator expression is cool (sort of >> like the lazy evaluation in Haskell) until I notice this side effect. >> >> >>>a=(x for x in range(2)) >> >>>list(a) >> [1,2] >> >>>list(a) >> [] >> >> Would this make generator/generator expression's usage pretty limited ? > > nope.
In fairness, it is a pretty big Gotcha. >> As when the program/system goes beyond a single module, this behaviour >> can cause subtle bugs ? > > sure, in the same way as > > >>> f = open(filename) > >>> f.read() > 'hello world\n' > >>> f.read() # oops! > '' > > causes subtle bugs (that is, almost never) Are you saying that the bugs it causes aren't subtle? *wink* -- Steven -- http://mail.python.org/mailman/listinfo/python-list
