numpy all differing from builtin all

Question

What is the reason for this weirdness in numpy's all?

>>> import numpy as np
>>> np.all(xrange(10))
False
>>> np.all(i for i in xrange(10))
True

Answer 1

Numpy.all does not understands generator expressions.

From the documentation

 numpy.all(a, axis=None, out=None)

    Test whether all array elements along a given axis evaluate to True.
    Parameters :    

    a : array_like

        Input array or object that can be converted to an array.