Index and select elements in 2D NumPy Array using Tuple of arrays
Indexing with a Tuple of Arrays:
Write a NumPy program that creates a 2D NumPy array and uses a tuple of arrays to index and select a specific set of elements.
Sample Solution:
Python Code:
import numpy as np
# Create a 2D NumPy array of shape (5, 5) with random integers
array_2d = np.random.randint(0, 100, size=(5, 5))
# Define row and column indices as a tuple of arrays
row_indices = np.array([0, 1, 2, 3])
col_indices = np.array([4, 3, 2, 1])
# Use the tuple of arrays to index and select specific elements
selected_elements = array_2d[row_indices, col_indices]
# Print the original array and the selected elements
print('Original 2D array:\n', array_2d)
print('Row indices:\n', row_indices)
print('Column indices:\n', col_indices)
print('Selected elements:\n', selected_elements)
Output:
Original 2D array: [[ 7 74 80 19 2] [63 29 42 4 36] [94 37 96 21 90] [28 81 62 7 66] [13 3 60 40 89]] Row indices: [0 1 2 3] Column indices: [4 3 2 1] Selected elements: [ 2 4 96 81]
Explanation:
- Import Libraries:
- Imported numpy as 'np' for array creation and manipulation.
- Create 2D NumPy Array:
- Create a 2D NumPy array named array_2d with random integers ranging from 0 to 99 and a shape of (5, 5).
- Define Row and Column Indices:
- Defined row_indices and col_indices arrays to specify the rows and columns from which to select elements.
- Tuple of Arrays Indexing:
- Used a tuple of arrays (row_indices, col_indices) to index and select specific elements from array_2d.
- Print Results:
- Print the original 2D array, the row and column indices, and the selected elements to verify the indexing operation.
Python-Numpy Code Editor:
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