NumPy: Create an 1-D array of 20 elements

NumPy: Array Object Exercise-175 with Solution

Reshape 1D array to 2D and restore.

Write a NumPy program to create an 1-D array of 20 elements. Now create a new array of shape (5, 4) from the said array, then restores the reshaped array into a 1-D array.

Sample Solution:

Python Code:

# Importing NumPy library
import numpy as np

# Creating a NumPy array using arange with values from 0 to 40 (exclusive) with a step of 2
array_nums = np.arange(0, 40, 2)

# Printing the original array
print("Original array:")
print(array_nums)

# Reshaping the array into a new shape (5 rows and 4 columns)
print("\nNew array of shape(5, 4):")
new_array = array_nums.reshape(5, 4)
print(new_array)

# Flattening the reshaped array back into a 1-D array
print("\nRestore the reshaped array into a 1-D array:")
print(new_array.flatten())

Sample Output:

Original array:
[ 0  2  4  6  8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38]

New array of shape(5, 4):
[[ 0  2  4  6]
 [ 8 10 12 14]
 [16 18 20 22]
 [24 26 28 30]
 [32 34 36 38]]

Restore the reshaped array into a 1-D array:
[ 0  2  4  6  8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38]

Explanation:

In the above example -

array_nums = np.arange(0, 40, 2): This code creates a 1-dimensional NumPy array containing even numbers from 0 to 38 (including 0 and excluding 40, with a step of 2).

new_array = array_nums.reshape(5, 4): This code reshapes the 1-dimensional array into a 2-dimensional array with 5 rows and 4 columns.print(new_array.flatten()): This code flattens the 2-dimensional array back into a 1-dimensional array by concatenating its rows, and then prints the result.

Python-Numpy Code Editor:

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