I guess I am thinking of it as an operation that I am preforming on a list and not making a new list. Also looking to learn better methods. This is difficult when you are working alone. It is difficult to know where to improve. The actual functions I am making are more complicated than this example. Thanks Vincent Davis 720-301-3003
On Thu, Mar 5, 2009 at 5:13 PM, Gabriel Genellina <gagsl-...@yahoo.com.ar>wrote: > En Thu, 05 Mar 2009 14:43:12 -0200, Vincent Davis < > vinc...@vincentdavis.net> escribió: > > > If I have a list and I what to make changes to it.a = [1,2,3,4,5,6,7,8,9] >> and maybe I want to drop the odd and double the even numbers and I will >> need to do this repeatedly. >> How is this best done? That is as a function or class. All I know how to >> do >> is >> >> def doubleeven(alist): >> blist = [2*x for x in a if x % 2 ==0] >> return blist >> >> then when I am using it I do this >> >> a = doubleeven(a) >> I what to keep it named "a" >> >> I am not sure if this is the best way in terms of format or structure. Is >> there a better way. >> > > I don't grasp what you're worried about... Your function does exactly what > you have specified above, so it's correct. Don't you like the fact that it > returns a *new* list instead of modifying the original one in-place? You may > use: > > a[:] = doubleeven(a) > > Or rewrite the function using a while loop (to avoid having two lists alive > at the same time), but I would not bother unless there are strong reasons > (the lists is really huge, or there is very few memory available). > > -- > Gabriel Genellina > > -- > http://mail.python.org/mailman/listinfo/python-list >
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