Remove duplicates from numpy array

In this numpy tutorial, we will discuss how to remove duplicates from the numpy array.

 

Introduction

numpy stands for numeric python which is used to perform mathematical operations on arrays.

It is a module in which we have to import from the python. 

Syntax to import:

import numpy

We can also use alias for the module 

For example,

import numpy as np

We can directly use np to call the numpy module.

Array

An array is an one dimensional data structure used to store single data type data.

I.E It will only store all integer data or all string type data.or all float type data.

We can create an numpy array by using array() function.

 

Syntax:

numpy.array(elements)

where, elements are the input data elements.

Method 1 : Using unique()

This is used to get the unique elements by removing duplicate elements in the given numpy array.

Syntax:

numpy.unique(array_input)

where, array_input is the input numpy array.

Example:

In this example, we will create an numpy array with integer elements( 5 duplicates ).

#import numpy module
import numpy

#create first numpy array with 10 elements
array_input1=numpy.array([1,2,3,4,5,3,2,4,5,2])

#display array
print(array_input1)

#display array by removing duplicates
print(numpy.unique(array_input1))

Output:

From the above array, there are 5 elements that contains duplicates - 3 2 4 5 2. So these are removed.

[1 2 3 4 5 3 2 4 5 2]
[1 2 3 4 5]

Method 2 : Using set()

This is used to get the unique elements by removing duplicate elements in the given numpy array. set will not allow duplicates. It will return the new set by removing duplicates from the numpy array

Syntax:

set(array_input)

where, array_input is the input numpy array.

Example:

In this example, we will create an numpy array with integer elements( 5 duplicates ) and remove duplicates using set().

#import numpy module
import numpy

#create first numpy array with 10 elements
array_input1=numpy.array([1,2,3,4,5,3,2,4,5,2])

#display array
print(array_input1)

#display array by removing duplicates
print(set(array_input1))

Output:

From the above array, there are 5 elements that contains duplicates - 3 2 4 5 2. So these are removed.

[1 2 3 4 5 3 2 4 5 2]
{1, 2, 3, 4, 5}