How Do I Consistently Flatten A Numpy Array?

from numpy import array, eye, matrix x = array([1, 0]) A = eye(2) print(A.dot(x)) prints [1. 0.]. On the other hand, B = matrix([[1, 0], [0, 1]]) print(B.dot(x)) prints [[1 0]]

Solution 1:

Stop using matrix. numpy.matrix.flatten returns a 1-row matrix, because that's as flat as matrix instances get. If for some reason you are dead set on using matrix, convert to ndarray with matrix.A before flattening:

flat = whatever_matrix.A.flatten()

or just use A1 to get a flat ndarray directly:

flat = whatever_matrix.A1