Matrix2026-04-27

My Solution: Exercism Matrix solution

Instructions

Given a string that represents a matrix of numbers, parse it into rows and columns.

Rows are separated by newlines, and the numbers in each row are separated by spaces. For example, the string:

9 8 7
5 3 2
6 6 7

represents the rows 9, 8, 7, 5, 3, 2, and 6, 6, 7.

Your program should be able to return:

• A list of the rows, reading each row left-to-right from top to bottom.
• A list of the columns, reading each column top-to-bottom from left to right.

Solution

class Matrix:
    matrix_array = []

    def __init__(self, matrix_string):
        self.matrix_array = []
        for row in matrix_string.split('\n'):
            matrix_row = []
            for num in row.split():
                matrix_row.append(int(num))

            self.matrix_array.append(matrix_row)

    def row(self, index):
        return self.matrix_array[index - 1]

    def column(self, index):
        res = []
        for row in self.matrix_array:
            res.append(row[index - 1])

        return res

Syntax Notes

• split('\n') breaks the matrix string into separate rows.
• split() on each row breaks that row into individual number strings.
• int(num) converts each string number into a real integer before storing it.
• row(index) and column(index) use 1-based indexing, so index - 1 converts the user-facing index into a Python list position.
• column(index) walks through each stored row and picks the same position from each one.