Calculate the mean across dimension in a 2D NumPy array

Last Updated : 29 Aug, 2020

We can find out the mean of each row and column of 2d array using numpy with the function np.mean(). Here we have to provide the axis for finding mean.

Syntax: numpy.mean(arr, axis = None)

For Row mean: axis=1

For Column mean: axis=0

Example:

Python3

# Importing Library import numpy as np  # creating 2d array arr = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])  # Calculating mean across Rows row_mean = np.mean(arr, axis=1)  row1_mean = row_mean[0] print("Mean of Row 1 is", row1_mean)  row2_mean = row_mean[1] print("Mean of Row 2 is", row2_mean)  row3_mean = row_mean[2] print("Mean of Row 3 is", row3_mean)   # Calculating mean across Columns column_mean = np.mean(arr, axis=0)  column1_mean = column_mean[0] print("Mean of column 1 is", column1_mean)  column2_mean = column_mean[1] print("Mean of column 2 is", column2_mean)  column3_mean = column_mean[2] print("Mean of column 3 is", column3_mean)

Output:

Mean of Row 1 is 2.0  Mean of Row 2 is 5.0  Mean of Row 3 is 8.0  Mean of column 1 is 4.0  Mean of column 2 is 5.0  Mean of column 3 is 6.0

Calculate the mean across dimension in a 2D NumPy array

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