Erik Lind wrote: > I see a more complicated thread on a similar sounding question, but my > question is simpler, I hope.
numpy questions are usually answered better on the numpy mailing list. http://www.scipy.org/Mailing_Lists > I have a large numpy matrix, initially created as: > > Mat = zeros((a,b), int) > > and a smaller array with other data > > Sub = [1,2,3,4,5],[6,7,8,9,0] > > I want to replace a section of Mat matrix with Sub matrix without having to > loop through each cell in each matrix individually. > > I thought index/slice assignments, should be able to do that, but I can only > get it to work (as per book examples) with simple arrays. Every syntax > combination I have tried gives one error or another, typically "can't > broadcast an object....", but intuitively it seems there should be a simple > solution. > > In short, how do I insert the data in the two (or any number of) rows in > Sub[0:2] into any part of Mat starting at Mat[x,y] without using "for" loops > ? In [11]: Sub = array([[1,2,3,4,5],[6,7,8,9,0]]) In [12]: Mat = zeros((10, 10), int) In [13]: Mat[5:5+2,4:4+5] = Sub In [14]: Mat Out[14]: array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 1, 2, 3, 4, 5, 0], [0, 0, 0, 0, 6, 7, 8, 9, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]) -- Robert Kern "I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth." -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
