On Sun, Aug 30, 2009 at 9:55 PM, elsa<kerensael...@hotmail.com> wrote: > Hi, > > i have a question about the built in map function. Here 'tis: > > say I have a list, myList. Now say I have a function with more than > one argument: > > myFunc(a, b='None') > > now, say I want to map myFunc onto myList, with always the same > argument for b, but iterating over a: > > map(myFunc(b='booHoo'), myList) > > Why doesn't this work?
Because myFunc is executed before map() is ever called, and you didn't specify a value for the `a` parameter, hence you get an error about not giving a value for `a`. Another way of saying this: Python uses "eager evaluation" (http://en.wikipedia.org/wiki/Eager_evaluation) most of the time. > is there a way to make it work? Use functools.partial to fill in the `b` parameter: http://docs.python.org/library/functools.html#functools.partial #untested example: from functools import partial f = partial(myFunc, b='booHoo') map(f, myList) Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
