NumPy: numpy.zeros_like() function

Last update on March 21 2023 12:08:40 (UTC/GMT +8 hours)

numpy.zeros_like() function

The numpy.zeros_like() function takes an array_like object as input and returns an array of the same shape, size, and dtype with all elements set to zero.

This function is useful when you want to create an array of zeros with the same shape and type as another array without explicitly specifying the shape and data type. It can also be used to initialize a new array with the same shape as an existing array but with all elements set to zero.

Syntax:

numpy.zeros_like(a, dtype=None, order=’K’, subok=True)

Parameters:

Name	Description	Required / Optional
a	The shape and data-type of a define these same attributes of the returned array.	Required
dtype	Overrides the data type of the result. New in version 1.6.0.	optional
order	Overrides the memory layout of the result. 'C' means C-order, 'F' means F-order, 'A' means 'F' if a is Fortran contiguous, 'C' otherwise. 'K' means match the layout of a as closely as possible. New in version 1.6.0.	optional
subok	If True, then the newly created array will use the sub-class type of 'a', otherwise it will be a base-class array. Defaults to True.	optional

Return value:

[ndarray] Array of zeros with the same shape and type as a.

Example: Creating an array of zeros with the same shape and data type as a given array using numpy.zeros_like()

>>> import numpy as np
>>> a = np.arange(4)
>>> a = a.reshape((2, 2))
>>> a
array([[0, 1],
       [2, 3]])
>>> np.zeros_like(a)
array([[0, 0],
       [0, 0]])

In the above code an array a is created using np.arange(4) and is reshaped into a 2x2 array using .reshape((2,2)). Next, numpy.zeros_like(a) is called, which returns an array of zeros with the same shape and data type as a. This means that the returned array will also be a 2x2 array of integers filled with zeros.

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Example: Creating an array of zeros with the same shape and data type as an existing array

>>> import numpy as np
>>> b = np.arange(5, dtype=float)
>>> b
array([ 0.,  1.,  2.,  3.,  4.])
>>> np.zeros_like(b)
array([ 0.,  0.,  0.,  0.,  0.])

Here the code creates a one-dimensional NumPy array b containing float values from 0 to 4 using the arange() function. Then, the zeros_like() function creates a new NumPy array of zeros with the same shape and data type as b. Since b is a one-dimensional array of length 5, zeros_like(b) also creates a one-dimensional array of the same length, containing all zeros and having the same data type (float).

Pictorial Presentation:

Python - NumPy Code Editor:

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