numpy.fromiter

numpy.fromiter(iterable, dtype, count=-1)

Create a new 1-dimensional array from an iterable object.

Parameters:	iterable : iterable object An iterable object providing data for the array. dtype : data-type The data-type of the returned array. count : int, optional The number of items to read from iterable. The default is -1, which means all data is read.
Returns:	out : ndarray The output array.

Notes

Specify count to improve performance. It allows fromiter to pre-allocate the output array, instead of resizing it on demand.

Examples

>>> iterable = (x*x for x in range(5))
>>> np.fromiter(iterable, np.float)
array([  0.,   1.,   4.,   9.,  16.])