How to generically transform a list?
Arthur Rambo
arambo314 at hotmail.com
Thu Aug 26 22:41:14 EDT 2004
As simple as
theList=[['a',1,11,'aa'], ['b',2,22,'bb'],['c',3,33,'cc']]
returnList=[2,1]
newList=[[item[index] for index in returnList] for item in theList]
Python rules...
> Suppose you have a list of lists:
>
> theList = [['a',1,11,'aa'], ['b',2,22,'bb'],['c',3,33,'cc']]
>
> I would like to have a GENERIC way how to turn this list of list into
> another list of list.
> - A user can choose which columns she wants
> - A user can select the order of the columns
>
> For example:
> The user wants columns: 1,2
> The user wants it to be ordered: 2,1
>
> A non generic approach would maybe do the following:
>
> >>> theList = [['a',1,11,'aa'], ['b',2,22,'bb'],['c',3,33,'cc']]
> >>> new_list = [[row[2], row[1]] for row in theList]
> >>> new_list
> [[11, 1], [22, 2], [33, 3]]
>
> I am sure there must be a rather elegant generic approach, which is
> lurking somewhere to be realeased.
>
> Thanks for any hint in advance,
> Marco
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