Select elements from 1D NumPy array using integer Indexing

NumPy: Advanced Indexing Exercise-2 with Solution

Integer Array Indexing:

Write a NumPy program that creates a 1D NumPy array and uses integer array indexing to select a subset of elements based on an index array.

Sample Solution:

Python Code:

import numpy as np

# Create a 1D NumPy array
array_1d = np.array([10, 20, 30, 40, 50, 60, 70, 80, 90, 100])

# Define an index array to select specific elements
index_array = np.array([0, 2, 4, 6, 8])

# Use integer array indexing to select elements
selected_elements = array_1d[index_array]

# Print the original array and the selected elements
print('Original 1D array:\n', array_1d)
print('Index array:\n', index_array)
print('Selected elements:\n', selected_elements)

Output:

Original 1D array:
 [ 10  20  30  40  50  60  70  80  90 100]
Index array:
 [0 2 4 6 8]
Selected elements:
 [10 30 50 70 90]

Explanation:

• Import libraries:
• Imported numpy as np for array creation and manipulation.
• Create 1D NumPy Array:
• Create a 1D NumPy array named array_1d with elements ranging from 10 to 100.
• Define Index Array:
• Define an index array index_array containing specific indices to select elements from array_1d.
• Integer Array Indexing:
• Used integer array indexing to select elements from array_1d based on index_array.
• Print Results:
• Finally print the original 1D array, the index array, and the selected elements to verify the indexing operation.

Python-Numpy Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Select elements from 2D NumPy array using Boolean indexing.
Next: Select elements from 3D NumPy array using Fancy indexing.