On Apr 11, 6:05 pm, ergconce...@googlemail.com wrote: > On Apr 11, 11:18 pm, George Sakkis <george.sak...@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?
Yes, use numpy.resize: >>> s = N.resize(my_list, (241,241)) You should probably be able to find the answer to most of your upcoming numpy questions at http://numpy.scipy.org/numpydoc/numpy.html (especially the array functions, http://numpy.scipy.org/numpydoc/numpy-9.html) George -- http://mail.python.org/mailman/listinfo/python-list
