data type not understood

I'm trying to use a matrix to compute stuff. The code is this

imp开发者_运维技巧ort numpy as np
# some code
mmatrix = np.zeros(nrows, ncols)
print mmatrix[0, 0]

but I get 'data type not understood', and it works if I do it from terminal.

Try:

mmatrix = np.zeros((nrows, ncols))

Since the shape parameter has to be an int or sequence of ints

http://docs.scipy.org/doc/numpy/reference/generated/numpy.zeros.html

Otherwise you are passing ncols to np.zeros as the dtype.