Numpy – Set All Values to Zero in Array

The Numpy library in Python comes with a number of built-in functions to manipulate the data in arrays. In this tutorial, we will look at a function that helps us set all the values in a Numpy array to zero.

How to set all values to zero in Numpy?

You can use the numpy.ndarray.fill() function to set all the values in a Numpy array to zero. Pass 0 as the argument (this is the value used to fill all the values in the array).

The following is the syntax –

# set all values in numpy array ar to 0
ar.fill(0)

It modifies the array in-place, filling each value with zero (the passed value).

Let’s now look at a step-by-step example of using the above function.

Step 1 – Create a Numpy array

First, we will create a Numpy array that we will use throughout this tutorial.

import numpy as np

# create a numpy array
ar = np.array([-2, -1, 0, 1, 2, 3, -4])
# display the array
print(ar)

Output:

[-2 -1  0  1  2  3 -4]

Here, we used the numpy.array() function to create a Numpy array containing some numbers.

Step 2 – Set each value to 0 using numpy.ndarray.fill()

Apply the numpy.ndarray.fill() function on the array and pass 0 as the parameter to set each value to zero in the array.

Let’s apply this function to the array created above.

# set all values to zero
ar.fill(0)
# display the array
print(ar)

Output:

[0 0 0 0 0 0 0]

You can see that each value in the array ar is now 0.

The numpy.ndarray.fill() function works similarly on higher-dimensional arrays. For example, let’s apply this function to a 2D array of some numbers.

# create 2D numpy array
ar = np.array([[-1, 2, -3],
               [0, 51, 7],
               [1, 125, 8]])
# set all values to zero
ar.fill(0)
# display the array
print(ar)

Output:

[[0 0 0]
 [0 0 0]
 [0 0 0]]

You can see that each value in the above 2D array is now zero.

You might also be interested in –

• Numpy – Get the Sign of Each Element in Array
• Get the Median of Numpy Array – (With Examples)
• Numpy – Get Standard Deviation of Array Values
• Numpy – Get Min Value in Array