How can I do something like the following? a = empty((5,7), dtype=<4 element array of floats>) c = a[:,-1] # last column of 4 element arrays a[0,0] = 2.0 print a[0,0] [2. 2. 2. 2.] a[1,0] = 3.0 a[0,1] = a[0,0] * a[1,0] print a[0,1] [6. 6. 6. 6.] etc. As always, thanks for the help! Alex