NumPy array creation: fromfunction() function

Last update on February 26 2020 08:08:51 (UTC/GMT +8 hours)

fromfunction() function

The fromfunction() function is used to 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).

Syntax:

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

Version: 1.15.0

Parameter:

Name	Description	Required / Optional
function	The function is called with N parameters, where N is the rank of shape. Each parameter represents the coordinates of the array varying along a specific axis. For example, if shape were (2, 2), then the parameters would be array([[0, 0], [1, 1]]) and array([[0, 1], [0, 1]])	Required
shape	Shape of the output array, which also determines the shape of the coordinate arrays passed to function.	Required
dtype	Data-type of the coordinate arrays passed to function. By default, dtype is float.	Optional

Return value:

fromfunction : any
The result of the call to function is passed back directly. Therefore the shape of fromfunction is completely determined by function. If function returns a scalar value, the shape of fromfunction would match the shape parameter.

Example-1: NumPy.fromfunction() method

>>> import numpy as np
>>> np.fromfunction(lambda i, j: i == j, (2, 3), dtype=int)
array([[ True, False, False],
       [False,  True, False]], dtype=bool)

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Example-2: NumPy.fromfunction() method

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

Pictorial Presentation:

Python - Numpy Code Editor:

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