NumPy ones()

Summary: in this tutorial, you’ll learn how to use the numpy `ones()` function to create a numpy array of a given shape whose elements are filled with ones.

The `ones()` function of the `numpy` module allows you to create a numpy array of a given shape whose elements are filled with ones.

For example, the following uses the `ones()` function to create an array with three axes, the first axis has two elements, the second axis has three elements, and the third axis has 4 elements:

`import numpy as np`

`a = np.ones((2, 3, 2)) print(a)`

Code language: Python (python)

Output:

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

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

Code language: Python (python)

By default, `ones()` function uses `float64` for its elements. For example:

`import numpy as np`

`a = np.ones((2, 3, 2)) print(a.dtype)`

Code language: Python (python)

Output:

`float64`

Code language: Python (python)

To use a different type, you need to specify it using the `dtype` argument. For example:

`import numpy as np`

`a = np.ones((2, 3, 4), dtype=np.int32) print(a) print(a.dtype)`

Code language: Python (python)

Output:

`[[[1 1] [1 1] [1 1]]`

` [[1 1] [1 1] [1 1]]] int32`

Code language: Python (python)

In this example, we use `int32` type for the elements. Therefore, you don’t see the decimal point (.) appearing on each number.

Summary

• Use numpy `ones()` function to create an array of a given shape whose elements are filled with ones.