NumPy: Extract first, third and fifth elements of the third and fifth rows from a given (6x6) array
Extract First, Third, Fifth Elements of Third/Fifth Rows of 6x6 Array
Write a NumPy program to extract the first, third and fifth elements of the third and fifth rows from a given (6x6) array.
Pictorial Presentation:
Sample Solution:
Python Code:
# Importing the NumPy library and aliasing it as 'np'
import numpy as np
# Creating a NumPy array 'arra_data' containing integers from 0 to 35 and reshaping it into a 6x6 matrix
arra_data = np.arange(0, 36).reshape((6, 6))
# Displaying a message indicating the original array will be printed
print("Original array:")
# Printing the original 6x6 array 'arra_data'
print(arra_data)
# Displaying a message indicating the extracted data (First, third, and fifth elements of the third and fifth rows)
print("\nExtracted data: First, third, and fifth elements of the third and fifth rows")
# Using slicing to extract a sub-array containing the first, third, and fifth elements of the third and fifth rows
print(arra_data[2::2, ::2])
Sample Output:
Original array: [[ 0 1 2 3 4 5] [ 6 7 8 9 10 11] [12 13 14 15 16 17] [18 19 20 21 22 23] [24 25 26 27 28 29] [30 31 32 33 34 35]] Extracted data: First, third and fifth elements of the third and fifth rows [[12 14 16] [24 26 28]]
Explanation:
In the above exercise -
arra_data = np.arange(0, 36).reshape((6, 6)): This line creates a 1-dimensional NumPy array with elements from 0 to 35 (excluding 36) using np.arange(0, 36) and then reshapes it into a 2-dimensional array with 6 rows and 6 columns using .reshape((6, 6)).
print(arra_data[2::2, ::2]): It prints a subarray of ‘arra_data’ by selecting rows starting from index 2 with a step of 2, and columns starting from index 0 with a step of 2 using slicing with a step.
The subarray consists of the elements at rows 2 and 4 and columns 0, 2, and 4 in the original array ‘arra_data’.
Python-Numpy Code Editor: