You can use the following methods to add one or more elements to a NumPy array:
Method 1: Append One Value to End of Array
#append one value to end of array
new_array = np.append(my_array, 15)
Method 2: Append Multiple Values to End of Array
#append multiple values to end of array
new_array = np.append(my_array, [15, 17, 18])
Method 3: Insert One Value at Specific Position in Array
#insert 95 into the index position 2 new_array = np.insert(my_array, 2, 95)
Method 4: Insert Multiple Values at Specific Position in Array
#insert 95 and 99 starting at index position 2 of the NumPy array new_array = np.insert(my_array, 2, [95, 99])
This tutorial explains how to use each method in practice with the following NumPy array:
import numpy as np
#create NumPy array
my_array = np.array([1, 2, 2, 3, 5, 6, 7, 10])
#view NumPy array
my_array
array([ 1, 2, 2, 3, 5, 6, 7, 10])
Example 1: Append One Value to End of Array
The following code shows how to use np.append() to append one value to the end of the NumPy array:
#append one value to end of array
new_array = np.append(my_array, 15)
#view new array
new_array
array([ 1, 2, 2, 3, 5, 6, 7, 10, 15])
The value 15 has been added to the end of the NumPy array.
Example 2: Append Multiple Values to End of Array
The following code shows how to use np.append() to append multiple values to the end of the NumPy array:
#append multiple values to end of array
new_array = np.append(my_array, [15, 17, 18])
#view new array
new_array
array([ 1, 2, 2, 3, 5, 6, 7, 10, 15, 17, 18])
The values 15, 17, and 18 have been added to the end of the NumPy array.
Example 3: Insert One Value at Specific Position in Array
The following code shows how to insert one value into a specific position in the NumPy array:
#insert 95 into the index position 2 new_array = np.insert(my_array, 2, 95) #view new array new_array array([ 1, 2, 95, 2, 3, 5, 6, 7, 10])
The value 95 has been inserted into index position 2 of the NumPy array.
Example 4: Insert Multiple Values at Specific Position in Array
The following code shows how to insert multiple values starting at a specific position in the NumPy array:
#insert 95 and 99 starting at index position 2 of the NumPy array new_array = np.insert(my_array, 2, [95, 99]) #view new array new_array array([ 1, 2, 95, 99, 2, 3, 5, 6, 7, 10])
The values 95 and 99 have been inserted starting at index position 2 of the NumPy array.
Additional Resources
The following tutorials explain how to perform other common tasks in NumPy:
How to Filter a NumPy Array
How to Remove NaN Values from NumPy Array
How to Compare Two NumPy Arrays