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NumPy: Transform a given array

NumPy: Basic Exercise-51 with Solution

Write a NumPy program to create a new array of given shape (5,6) and type, filled with zeros.
Change the said array in the following format:

Given array:
[[0 0 0 0 0 0]
[0 0 0 0 0 0]
[0 0 0 0 0 0]
[0 0 0 0 0 0]
[0 0 0 0 0 0]]
New array:
[[3 0 3 0 3 0]
[7 0 7 0 7 0]
[3 0 3 0 3 0]
[7 0 7 0 7 0]
[3 0 3 0 3 0]]

Sample Solution:

Python Code :

# Importing the NumPy library with an alias 'np'
import numpy as np

# Creating a NumPy array 'nums' with shape (5, 6) filled with zeros of integer type
nums = np.zeros(shape=(5, 6), dtype='int')

# Printing a message indicating the original array
print("Original array:")
print(nums)

# Assigning value 3 to every alternate row and column starting from index 0
nums[::2, ::2] = 3

# Assigning value 7 to every alternate row starting from index 1 and every column starting from index 0
nums[1::2, ::2] = 7

# Printing the updated array after assigning values 3 and 7
print("\nNew array:")
print(nums) 

Sample Output:

Original array:
[[0 0 0 0 0 0]
 [0 0 0 0 0 0]
 [0 0 0 0 0 0]
 [0 0 0 0 0 0]
 [0 0 0 0 0 0]]

New array:
[[3 0 3 0 3 0]
 [7 0 7 0 7 0]
 [3 0 3 0 3 0]
 [7 0 7 0 7 0]
 [3 0 3 0 3 0]]

Explanation:

In the above code –

np.zeros(shape=(5, 6), dtype='int') creates a 5x6 2D array filled with zeros of integer type and stores in the variable ‘nums’

nums[::2, ::2] = 3: This line sets every second element in every second row, starting from the first row (0-th index), to the value 3.

nums[1::2, ::2] = 7: This line sets every second element in every second row, starting from the second row (1-st index), to the value 7.

Python-Numpy Code Editor:

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