python3 顺时针打印矩阵元素

code

'''
输入一个矩阵，按照从外向里以顺时针的顺序依次打印出每一个数字，
例如，如果输入如下矩阵：
[[ 1,  2,  3,  4],
 [ 5,  6,  7,  8],
 [ 9, 10, 11, 12],
 [13, 14, 15, 16]]
则依次打印出数字 1,2,3,4,8,12,16,15,14,13,9,5,6,7,11,10.
'''

# -*- coding:utf-8 -*-
class Solution:
    # matrix类型为二维列表，需要返回列表
    def printMatrix(self, matrix):
        if matrix == None:
            return
        rows = len(matrix)
        columns = len(matrix[0])
        start = 0
        while rows > start * 2 and columns > start * 2:
            self.PrintMatrixInCircle(matrix, columns, rows, start)
            start += 1
        print('')

    def PrintMatrixInCircle(self, matrix, columns, rows, start):
        endX = columns - 1 - start
        endY = rows - 1 - start

        # 从左到右打印一行
        for i in range(start, endX+1):
            number = matrix[start][i]
            print("right",number, ' ', end='')

        # 从上到下打印一行
        if start < endY:
            for i in range(start+1, endY+1):
                number = matrix[i][endX]
                print("down",number, ' ', end='')

        # 从右到左打印一行
        if start < endX and start < endY:
            for i in range(endX-1, start-1, -1):
                number = matrix[endY][i]
                print("left",number, ' ', end='')

        # 从下到上打印一行
        if start < endX and start < endY-1:
            for i in range(endY-1, start, -1):
                number = matrix[i][start]
                print("up",number, ' ', end='')


matrix = [[1,  2,  3,  4],
          [5,  6,  7,  8],
          [9, 10, 11, 12],
          [13, 14, 15, 16]]

matrix2 = [[1],[2],[3],[4],[5]]

matrix3 = [[1,2],
            [3,4],
            [5,6],
            [7,8],
            [9,10]]

S = Solution()
S.printMatrix(matrix)
S.printMatrix(matrix2)
S.printMatrix(matrix3)

outputs

macname@MacdeMBP ~ % python3 test.py
right 1  right 2  right 3  right 4  down 8  down 12  down 16  left 15  left 14  left 13  up 9  up 5  right 6  right 7  down 11  left 10  
right 1  down 2  down 3  down 4  down 5  
right 1  right 2  down 4  down 6  down 8  down 10  left 9  up 7  up 5  up 3  
macname@MacdeMBP ~ %