You are comparing a normal python list to a constant, which are obviously unequal. Try converting your lists to arrays first (untested):
import numeric/numpy as N a =N.array([0,1,2,5,6,6]) b = N.array([5,4,1,6,4,6]) print a==6 and b==6 print N.where(a==6 and b==6) hth, Bas Sheldon wrote: > Hi, > > I have two arrays that are identical and contain 1s and zeros. Only the > ones are valid and I need to know where both arrays have ones in the > same position. I thought logical_and would work but this example proves > otherwise: > >>> a = [0,1,2,5,6,6] > >>> b = [5,4,1,6,4,6] > >>> Numeric.logical_and(a==6,b==6) > 0 > >>> Numeric.where(a==b,1,0) > 0 > >>> Numeric.where(a==6 and b==6,1,0) > 0 > > The where() statement is also worhtless here. Does anyone have any > suggestion on how to do this? > > Thanks in advance, > Sheldon -- http://mail.python.org/mailman/listinfo/python-list