absolute newbie: divide a list into sublists (nested lists?) of fixed length

[ergconcepts at googlemail.com]

On Apr 11, 11:18 pm, George Sakkis <george.sak... at gmail.com> wrote:

> The numpy import *is* important if you want to use numpy-specific
> features; there are many "tricks" you can do easily with numpy arrays
> that you have to write manually for, say, regular python lists. For
> example what you want to do is trivial with numpy:
>
> >>>import numpy as N
> >>> s = N.array([ 0.84971586,  0.05786009,  0.9645675,  0.84971586,  0.05786009,
>
> 0.9645675, 0.84971586,  0.05786009,  0.9645675,  0.84971586,
> 0.05786009,  0.9645675])>>> # convert to a 4by3 array in place
> >>> s.shape = (4,3)
> >>> s
>
> array([[ 0.84971586,  0.05786009,  0.9645675 ],
>        [ 0.84971586,  0.05786009,  0.9645675 ],
>        [ 0.84971586,  0.05786009,  0.9645675 ],
>        [ 0.84971586,  0.05786009,  0.9645675 ]])

Thanks very much - works fine! Now for a follow-up question:)

Actually my original list called "mylist" contains 81217 elements - I
shape those into

>>> len(mylist)
81217
>>> s = N.array(mylist)
>>> s.shape = (241,337)

which works because the "total size of new array must be
unchanged" (241x337=81217)

Now this "matrix" actually is a 2D colorcoded map - I want to plot
this using the imshow splot routine in mayavi2..

However, there might be a problem: I believe that sometimes my
original array will not exactly contain 81217 elements, but maybe only
81216 or so. Nevertheless, I know that time x times y - structure will
always be the same (that is, 241 columns). What is of interest to me
is the first 241 x 241 part of the matrix anyway. Is there an easy way
to reshape my original array into a symmetric 241x241 matrix?

Thanks a lot again,

Bernard