Select column from a list
Stephen Fairchild
somebody at somewhere.com
Fri Aug 28 14:57:28 EDT 2009
hoffik wrote:
>
> Hello,
>
> I'm quite new in Python and I have one question. I have a 2D matrix of
> values stored in list (3 columns, many rows). I wonder if I can select one
> column without having to go through the list with 'for' command.
>
> For example I have list called 'values'.
> When I write 'values[0]' or 'values[0][:]' I'll get the first row.
> But when I write 'values[:][0]' I won't get the first column, but the
> first row again! I can't see why.
rows = [(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]
cols = zip(*rows)
To just get the second column:
zip(*rows)[1]
--
Stephen Fairchild
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