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Concatenate a NumPy array to another NumPy array

Concatenation of NumPy Arrays: In this tutorial, we will learn how to concatenate a NumPy array to another NumPy array with the help of examples. By Pranit Sharma Last updated : June 04, 2023

Problem Statement

Given two or more NumPy arrays of the same shapes, we have to concatenate them into one NumPy array.

Solution: How to concatenate a NumPy array to another NumPy array?

To concatenate a NumPy array to another NumPy array, you can use the numpy.concatenate() method by passing the given arrays. This will return an array by concatenating the given arrays.

Example 1: Concatenate two one-dimensional NumPy arrays

Consider the below-given program to concatenate two given 1D NumPy arrays.

# Import numpy
import numpy as np

# Create two 1D numpy arrays
arr1 = np.array([10, 20, 30, 40, 50])
arr2 = np.array([60, 70, 80, 90, 100])

# Printing the arrays
print("arr1\n", arr1)
print("arr2\n", arr2)

# Concatenate these given arrays
result = np.concatenate((arr1, arr2))

# Printing the result
print("Concatenated array (result):\n", result)

Output

arr1
 [10 20 30 40 50]
arr2
 [ 60  70  80  90 100]
Concatenated array (result):
 [ 10  20  30  40  50  60  70  80  90 100]

Example 2: Concatenate two two-dimensional NumPy arrays

Consider the below-given program to concatenate two given 2D NumPy arrays.

# Import numpy
import numpy as np

# Create two 2D numpy arrays
arr1 = np.array([[1, 2, 3], [4, 5, 6]])
arr2 = np.array([[9, 8, 7], [6, 5, 4]])

# Printing the arrays
print("arr1\n", arr1)
print("arr2\n", arr2)

# Concatenate these given arrays
result = np.concatenate((arr1, arr2))

# Printing the result
print("Concatenated array (result):\n", result)

Output

arr1
 [[1 2 3]
 [4 5 6]]
arr2
 [[9 8 7]
 [6 5 4]]
Concatenated array (result):
 [[1 2 3]
 [4 5 6]
 [9 8 7]
 [6 5 4]]

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