On Mon, Jun 21, 2010 at 17:42, Neal Becker <[email protected]> wrote: > Robert Kern wrote: > >> On Mon, Jun 21, 2010 at 14:01, Neal Becker <[email protected]> wrote: >>> Can I find an efficient way to do this? >>> >>> I have a 2d array, A, 80 rows by 880 columns. >>> >>> I have a vector, B, of length 80, with scalar indexes. >> >> I assume you mean 880. >> >>> I want a vector output C where >>> C[i] = A[b[i],i] (i=0,879) >> >> C = A[b, np.arange(880)] >> > > Thanks! Just what I needed. > > I wouldn't have guessed this. Do we have a wiki to save useful examples > like this?
This kind of indexing is documented here: http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html#integer Various examples are on the wiki here: http://www.scipy.org/Cookbook/Indexing -- 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 _______________________________________________ NumPy-Discussion mailing list [email protected] http://mail.scipy.org/mailman/listinfo/numpy-discussion
