NumPy: Extract all the elements of the first and fourth columns from a given (4x4) array
NumPy: Array Object Exercise-142 with Solution
Write a NumPy program to extract all the elements of the first and fourth columns from a given (4x4) 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 15 and reshaping it into a 4x4 matrix
arra_data = np.arange(0, 16).reshape((4, 4))
# Displaying a message indicating the original array will be printed
print("Original array:")
# Printing the original 4x4 array 'arra_data'
print(arra_data)
# Displaying a message indicating the extracted data (all the elements of the first and fourth columns)
print("\nExtracted data: All the elements of the first and fourth columns")
# Using slicing to extract all rows and specific columns (1st and 4th columns) from 'arra_data'
print(arra_data[:, [0, 3]])
Sample Output:
Original array: [[ 0 1 2 3] [ 4 5 6 7] [ 8 9 10 11] [12 13 14 15]] Extracted data: All the elements of the first and fourth columns [[ 0 3] [ 4 7] [ 8 11] [12 15]]
Explanation:
In the above code -
arra_data = np.arange(0, 16).reshape((4, 4)): It creates a 1-dimensional NumPy array with elements from 0 to 15 (excluding 16) using np.arange(0, 16) and then reshapes it into a 2-dimensional array with 4 rows and 4 columns using .reshape((4, 4)).
print(arra_data[:, [0, 3]]): This line prints specific columns of ‘arra_data’ by selecting all rows (indicated by :) and only the columns with indices 0 and 3 (indicated by [0, 3]).
Python-Numpy Code Editor:
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