Python Program for Program to Print Matrix in Z form

Last Updated : 29 Nov, 2022

Given a square matrix of order n*n, we need to print elements of the matrix in Z form

Examples:

Input : mat[][] =  {1, 2, 3,
                    4, 5, 6,
                    7, 8, 9}
Output : 1 2 3 5 7 8 9

Input : mat[][] = {5, 19, 8, 7,
                   4, 1, 14, 8,
                   2, 20, 1, 9,
                   1, 2, 55, 4}
Output: 5 19 8 7 14 20 1 2 55 4

Python3

# Python program to print a
# square matrix in Z form

arr = [[4, 5, 6, 8],
       [1, 2, 3, 1],
       [7, 8, 9, 4],
       [1, 8, 7, 5]]

n = len(arr[0])

i = 0
for j in range(0, n-1):
    print(arr[i][j], end=" ")

k = 1
for i in range(0, n):
    for j in range(n, 0, -1):
        if(j == n-k):
            print(arr[i][j], end=" ")
            break
    k += 1

# Print last row
i = n-1
for j in range(0, n):
    print(arr[i][j], end=" ")

# Code contributed by Mohit Gupta_OMG <(0_o)>

Output

4 5 6 8 3 8 1 8 7 5

Time complexity: O(n²) for a given square matrix of order n*n

Auxiliary Space: O(1)

Please refer complete article on Program to Print Matrix in Z form for more details!

Using numpy

numpy has several efficient ways to extract rows and diagonals, as illustrated below as follows:

Python3

import numpy as np

# This function shall print the given matrix in Z-form


def printZform(matrix):

    # Converting the matrix to np array
    matrix = np.array(matrix)

    # Printing the first row, the opposite diagonal, and the last row of the matrix
    print(*matrix[0], *np.diag(np.fliplr(matrix))[1:-1], *matrix[-1])


# Driver Code
arr = [[4, 5, 6, 8],
       [1, 2, 3, 1],
       [7, 8, 9, 4],
       [1, 8, 7, 5]]

printZform(arr)