#!/usr/bin/env python
# coding:UTF-8
 
 
"""
@version: python3.x
@author:曹新健
@contact: 617349013@qq.com
@software: PyCharm
@file: 二维列表下标互换（矩阵转置）.py
@time: 2018/12/30 10:24
"""
'''
矩阵转置
将[[1,2,3],[4,5,6],[7,8,9]]
转换为[[1,4,7],[2,5,8],[3,6,9]]
'''
 
'''
#方法一：默认列表值均初始为0，防止换为位置时，坐标越界
list1 = [[1,2,3],[4,5,6],[7,8,9]]
list2 = [[0,0,0],[0,0,0],[0,0,0]]
for i in range(3):
  for j in range(3):
    list2[j][i] = list1[i][j]
print(list2)
'''
 
'''
#方法二：互换位置，空列表插入值
list1 = [[1,2,3],[4,5,6],[7,8,9]]
list2 = [[],[],[]]
for i in range(3):
  for j in range(3):
    list2[j].insert(i,list1[i][j])
print(list2)
'''
 
'''
#方法三：行列互换
list1 = [[1,2,3],[4,5,6],[7,8,9]]
print([[list1[j][i] for i in range(3)] for j in range(3)])
'''
 
#方法四:取每行的第i列，即列转换为行
list1 = [[1,2,3],[4,5,6],[7,8,9]]
print([[row[i] for row in list1] for i in range(3)])