如何在Python中反向遍历列表?所以我可以从集合[len(collection)-1]开始,到集合[0]结束。

我还希望能够访问循环索引。


当前回答

如果不重新创建一个新列表,你可以通过索引:

>>> foo = ['1a','2b','3c','4d']
>>> for i in range(len(foo)):
...     print foo[-(i+1)]
...
4d
3c
2b
1a
>>>

OR

>>> length = len(foo)
>>> for i in range(length):
...     print foo[length-i-1]
...
4d
3c
2b
1a
>>>

其他回答

>>> l = ["a","b","c","d"]
>>> l.reverse()
>>> l
['d', 'c', 'b', 'a']

OR

>>> print l[::-1]
['d', 'c', 'b', 'a']

一个简单的方法:

n = int(input())
arr = list(map(int, input().split()))

for i in reversed(range(0, n)):
    print("%d %d" %(i, arr[i]))

其他答案都不错,但如果你想这么做 列表理解风格

collection = ['a','b','c']
[item for item in reversed( collection ) ]

作为python的初学者,我发现这种方法更容易理解,并且可以反转列表。

= = 1, 2, 3, 4

对于I在range(len(numlst)-1,-1,-1):

ie., for i in range(3,-1,-1), where 3 is length of list minus 1,
second -1 means list starts from last element and 
third -1 signifies it will traverse in reverse order.

打印(numlst[I])

O /p = 4,3,2,1

如果你不介意指数为负,你可以这样做:

>>> a = ["foo", "bar", "baz"]
>>> for i in range(len(a)):
...     print(~i, a[~i]))
-1 baz
-2 bar
-3 foo