Python_二维数组

 1 a = [[i for i in range(4)] for n in range(4)]
 2 print(a)
 3 # 遍历大序列
 4 for a_index, w in enumerate(a):            # enumaerate()遍历数据对象，同时列出数据和数据下标
 5      # 遍历大序列里的小序列
 6     for m_index in range(a_index, len(w)):    # range(w_index, )使for循环从w_index行开始替换
 7         tmp = a[m_index][a_index]      # 将大序列里的值存起来
 8         a[m_index][a_index] = w[a_index]          # 将小序列的值放到大序列
 9         a[a_index][m_index] = tmp            #将存起来的值放到小序列里
10     print('----------------')
11     for r in a:                         #查看转换过程
12         print(r)

[[0, 1, 2, 3], [0, 1, 2, 3], [0, 1, 2, 3], [0, 1, 2, 3]]
----------------
[0, 0, 0, 0]
[0, 1, 2, 3]
[0, 1, 2, 3]
[0, 1, 2, 3]
----------------
[0, 0, 0, 0]
[0, 1, 1, 1]
[0, 1, 2, 3]
[0, 1, 2, 3]
----------------
[0, 0, 0, 0]
[0, 1, 1, 1]
[0, 1, 2, 2]
[0, 1, 2, 3]
----------------
[0, 0, 0, 0]
[0, 1, 1, 1]
[0, 1, 2, 2]
[0, 1, 2, 3]