numpy.fromfunction

numpy.fromfunction(function, shape, **kwargs)

Construct an array by executing a function over each coordinate.

The resulting array therefore has a value fn(x, y, z) at coordinate (x, y, z).

Parameters:

function : callable

The function is called with N parameters, each of which represents the coordinates of the array varying along a specific axis. For example, if shape were (2, 2), then the parameters would be two arrays, [[0, 0], [1, 1]] and [[0, 1], [0, 1]]. function must be capable of operating on arrays, and should return a scalar value.

shape : (N,) tuple of ints

Shape of the output array, which also determines the shape of the coordinate arrays passed to function.

dtype : data-type, optional

Data-type of the coordinate arrays passed to function. By default, dtype is float.

Returns:

out : any

The result of the call to function is passed back directly. Therefore the type and shape of out is completely determined by function.

See also

indices, meshgrid

Notes

Keywords other than shape and dtype are passed to function.

Examples

>>> np.fromfunction(lambda i, j: i == j, (3, 3), dtype=int)
array([[ True, False, False],
       [False,  True, False],
       [False, False,  True]], dtype=bool)

>>> np.fromfunction(lambda i, j: i + j, (3, 3), dtype=int)
array([[0, 1, 2],
       [1, 2, 3],
       [2, 3, 4]])