On 9/8/2010 12:17 PM Andreas Waldenburger said...
On Wed, 8 Sep 2010 15:11:51 -0400 Benjamin Kaplan
<benjamin.kap...@case.edu> wrote:
There is no simple way to get [1,4,7] because it is just a list of
lists and not an actual matrix. You have to extract the elements
yourself.
col = []
for row in a:
col.append(row[0])
You can do this in one line using a list comprehension:
[ row[0] for row in a ]
I would suggest this (esp. the list comprehension version) over my
suggestion of zip(). WAAAYYYY more readable. Apparently I'm getting
rusty.
zip is very handy for inverting rows and cols (x's and y's, whatever)
>>> a = [(1,2),(3,4),(5,6),(7,8),(9,10)]
>>> zip(*a)
[(1, 3, 5, 7, 9), (2, 4, 6, 8, 10)]
So, I like zip if you're dealing with a in a matrix-ish manner, and list
comps for picking selected items out of a list.
Emile
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