Create Array with Ones in Numpy

NumPy - Create array with ones

To create a numpy array of specific shape with all the elements initialised to one in Python, we can use numpy.ones() function.

Call numpy.ones() function, and pass the shape (a tuple with lengths of dimensions) as argument to the the function.

Examples

1. Create array with ones of shape (3, 5)

In the following program, we create a numpy array (a 2 dimensional) with all elements in the array set to one, and a shape of (3, 5).

Python Program

import numpy as np

shape = (3, 5)
arr = np.ones(shape)

print(arr)

Output

[[1. 1. 1. 1. 1.]
 [1. 1. 1. 1. 1.]
 [1. 1. 1. 1. 1.]]

2. Create array with ones of shape (2, 3, 5)

In the following program, we create a numpy array , a 3-dimensional, with all elements in the array set to one, and a shape of (2, 3, 5).

Python Program

import numpy as np

shape = (2, 3, 5)
arr = np.ones(shape)

print(arr)

Output

[[[1. 1. 1. 1. 1.]
  [1. 1. 1. 1. 1.]
  [1. 1. 1. 1. 1.]]

 [[1. 1. 1. 1. 1.]
  [1. 1. 1. 1. 1.]
  [1. 1. 1. 1. 1.]]]

Summary

In this NumPy Tutorial, we learned how to create a numpy array with ones in Python using numpy.ones() function.