翻转一个数组并反转每一秒

时间:2015-04-01 06:23:56

标签: python matrix

基本上我在python中有一个矩阵'例子' (虽然大得多)。我需要制作阵列' example_what_I_want'用一些python代码。我想for循环是有序的 - 但我怎么能这样做呢?

example= 
[1,2,3,4,5],
[6,7,8,9,10],
[11,12,13,14,15],
[16,17,18,19,20],
[21,22,23,24,25]

example_what_I_want = 
[25,24,23,22,21],
[16,17,18,19,20],
[15,14,13,12,11],
[6,7,8,9,10],
[5,4,3,2,1]

所以它以蛇的方式增加。第一行必须颠倒!然后按照那种模式。

谢谢!

2 个答案:

答案 0 :(得分:5)

我假设example实际上是:

example = [[1,2,3,4,5],
           [6,7,8,9,10],
           [11,12,13,14,15],
           [16,17,18,19,20],
           [21,22,23,24,25]]

在这种情况下你可以这样做:

swapped_example = [sublst if idx%2 else sublst[::-1] for
                   idx,sublst in enumerate(example)][::-1]

哪个会给你:

In [5]: swapped_example
Out[5]: 
[[25, 24, 23, 22, 21],
 [16, 17, 18, 19, 20],
 [15, 14, 13, 12, 11],
 [6, 7, 8, 9, 10],
 [5, 4, 3, 2, 1]]

答案 1 :(得分:1)

或者,你可以使用它。

a = [[1,2,3,4,5],
[6,7,8,9,10],
[11,12,13,14,15],
[16,17,18,19,20],
[21,22,23,24,25]]

b = []

rev_a = iter(a[::-1])

while rev_a:
    try:
        b.append(rev_a.next()[::-1])
        b.append(rev_a.next())
    except StopIteration:
        break

print b

修改(之前不知道。@ Adam),

a = iter(a)
while a:
    try:
        b.insert(0, a.next()[::-1])
        b.insert(0, a.next())
    except StopIteration:
        break

print b[::-1]