NumPy ndarray.size Attribute

The NumPy ndarray.size attribute is used to get the total number of elements in a NumPy array. It returns an integer value representing the total count of elements, which is the product of the sizes of all dimensions of the array.

The size attribute is a simple and efficient way to determine the total number of elements in the array.

Usage of the size Attribute in NumPy

The size attribute can be accessed directly from a NumPy array object to find out how many elements the array contains.

It is commonly used when performing element-wise operations, reshaping arrays, or verifying the total number of elements in a multi-dimensional array.

Below are some examples that demonstrate how size can be applied to various arrays in NumPy.

Example: Basic Usage of size Attribute

In this example, we create a simple 1-dimensional array and use the size attribute to find out the total number of elements it contains −

import numpy as np

# Creating a 1-dimensional array
arr = np.array([1, 2, 3, 4])
print(arr.size)

Following is the output obtained −

4

Example: Checking the Size of a 2D Array

In this example, we create a 2-dimensional array and use the size attribute to determine the total number of elements −

import numpy as np

# Creating a 2-dimensional array
arr = np.array([[1, 2, 3], [4, 5, 6]])
print(arr.size)

This will produce the following result −

6

Example: Size of a Higher Dimensional Array

In this example, we create a 3-dimensional array and use the size attribute to find the total number of elements −

import numpy as np

# Creating a 3-dimensional array
arr = np.array([[[1, 2], [3, 4]], [[5, 6], [7, 8]]])
print(arr.size)

Following is the output of the above code −

8

Example: size with Empty Arrays

In the following example, we check the size of an empty array. This demonstrates that even an empty array has a defined size −

import numpy as np

# Creating an empty array
arr = np.array([])
print(arr.size)

The output obtained is as shown below −

0