A gotcha: Python pain point?
bjorns at gmail.com
Tue Jun 12 01:33:56 CEST 2007
Consider this example:
>>> def funcs(x):
... for i in range(5):
... def g(): return x + i
... yield g
I would expect the value of x used in g to be that at the function
declaration time, as if you've pass g a (x=x) argument, especially
after reading this post: http://lua-users.org/wiki/LuaScopingDiscussion
>>> [ fun() for fun in list(funcs(1)) ]
[5, 5, 5, 5, 5]
>>> [ fun() for fun in funcs(1) ]
[1, 2, 3, 4, 5]
This came up while discussing Python pain points at
I can see how it works now, but I haven't found an easy-to-read
documentation on this.
I guess it's debatable if perhaps every i used in the loop shouldn't
be a different i. It had me fooled, anyways.
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