# mean() Function of NumPy Library in Python (3 Examples)

In this article, I’ll illustrate how to **apply the mean function of the NumPy library** in the Python programming language.

The article contains three examples for the application of the mean function of the NumPy library. To be more precise, the article contains these content blocks:

Let’s do this…

## Example Data & Add-On Libraries

We first need to load the NumPy library:

import numpy as np # Import NumPy library in Python |

import numpy as np # Import NumPy library in Python

Now, we can create a NumPy array as shown below:

my_array = np.array([[1, 2, 3], [4, 5, 6]]) # Create example array print(my_array) # Print example array # [[1 2 3] # [4 5 6]] |

my_array = np.array([[1, 2, 3], [4, 5, 6]]) # Create example array print(my_array) # Print example array # [[1 2 3] # [4 5 6]]

## Example 1: Mean of All Values in NumPy Array

This example demonstrates how to get the mean of all values in a NumPy array.

For this task, we can apply the mean function of the NumPy library as shown below:

print(np.mean(my_array)) # Get mean of all array values # 3.5 |

print(np.mean(my_array)) # Get mean of all array values # 3.5

The previous output shows our result, i.e. the mean value of all elements in our array is 3.5.

## Example 2: Mean of Columns in NumPy Array

In Example 2, I’ll show how to find the means for each column in a NumPy array.

For this task, we have to specify the axis argument within the mean command to be equal to 0:

print(np.mean(my_array, axis = 0)) # Get mean of array columns # [2.5 3.5 4.5] |

print(np.mean(my_array, axis = 0)) # Get mean of array columns # [2.5 3.5 4.5]

## Example 3: Mean of Rows in NumPy Array

In this example, I’ll explain how to calculate the mean value of a NumPy array by row.

To accomplish this, we have to set the axis argument of the mean function to 1:

print(np.mean(my_array, axis = 1)) # Get mean of array rows # [2. 5.] |

print(np.mean(my_array, axis = 1)) # Get mean of array rows # [2. 5.]

## Video, Further Resources & Summary

Do you need more explanations on the examples of this article? Then you may want to have a look at the following video on my YouTube channel. In the video, I illustrate the Python code of this tutorial.

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Additionally, you could have a look at some of the related articles on my website:

- Calculate Mean in Python
- Mean of Columns & Rows of pandas DataFrame
- Calculate Mean by Group in Python
- Python Programming Examples

In this Python tutorial you have learned how to **use the mean function of the NumPy library**. If you have additional questions, tell me about it in the comments.