How to Remove Duplicate Elements from NumPy Array


You can use the following methods to remove duplicate elements in NumPy:

Method 1: Remove Duplicate Elements from NumPy Array

new_data = np.unique(data)

Method 2: Remove Duplicate Rows from NumPy Matrix

new_data = np.unique(data, axis=0)

Method 3: Remove Duplicate Columns from NumPy Matrix

new_data = np.unique(data, axis=1)

The following examples show how to use each method in practice.

Example 1: Remove Duplicate Elements from NumPy Array

The following code shows how to remove duplicate elements from a NumPy array:

import numpy as np

#create NumPy array
data = np.array([1, 1, 1, 2, 2, 4, 5, 5, 5, 5, 7, 8])

#create new array that removes duplicates
new_data = np.unique(data)

#view new array
print(new_data)

[1 2 4 5 7 8]

Notice that all duplicates have been removed from the NumPy array and only unique values remain.

Example 2: Remove Duplicate Rows from NumPy Matrix

The following code shows how to remove duplicate rows from a NumPy matrix:

import numpy as np

#create NumPy matrix
data = np.array([[1, 5, 5, 8],
                 [1, 5, 5, 8],
                 [6, 2, 3, 4],
                 [6, 2, 3, 4]])

#create new array that removes duplicate rows
new_data = np.unique(data, axis=0)

#view new matrix
print(new_data)

[[1 5 5 8]
 [6 2 3 4]]

Notice that all duplicate rows have been removed from the NumPy matrix and only unique rows remain.

Example 3: Remove Duplicate Columns from NumPy Matrix

The following code shows how to remove duplicate columns from a NumPy matrix:

import numpy as np

#create NumPy matrix
data = np.array([[1, 1, 5, 8, 1],
                 [1, 1, 2, 6, 1],
                 [4, 4, 3, 8, 4]])

#create new matrix that removes duplicate columns
new_data = np.unique(data, axis=1)

#view new matrix
print(new_data)

[[1 5 8]
 [1 2 6]
 [4 3 8]]

Notice that all duplicate columns have been removed from the NumPy matrix and only unique columns remain.

Additional Resources

The following tutorials explain how to perform other common tasks in NumPy:

How to Fill NumPy Array with Values
How to Remove Specific Elements from NumPy Array
How to Replace Elements in NumPy Array
How to Get Specific Row from NumPy Array

Leave a Reply

Your email address will not be published.