pyhton中实现列表元素顺序颠倒

 

1、循环

>>> test1 = ["aa","bb","cc","dd","ee","ff","gg"]
>>> test1
['aa', 'bb', 'cc', 'dd', 'ee', 'ff', 'gg']
>>> test2 = []
>>> test2
[]
>>> for i in range(-1,-(len(test1)+1),-1):
    test2.append(test1[i])

    
>>> test2
['gg', 'ff', 'ee', 'dd', 'cc', 'bb', 'aa']

 

2、列表分片

>>> test1[::1]
['aa', 'bb', 'cc', 'dd', 'ee', 'ff', 'gg', 'hh', 'ii', 'jj']
>>> test1[::-1]
['jj', 'ii', 'hh', 'gg', 'ff', 'ee', 'dd', 'cc', 'bb', 'aa']

 

3、就地反转

>>> test1 = ["aaa","bbb","ccc","ddd"]
>>> test1
['aaa', 'bbb', 'ccc', 'ddd']
>>> test2 = test1[:]
>>> test2
['aaa', 'bbb', 'ccc', 'ddd']
>>> test1.reverse()
>>> test1
['ddd', 'ccc', 'bbb', 'aaa']
>>> test2[::-1]
['ddd', 'ccc', 'bbb', 'aaa']
>>> test2
['aaa', 'bbb', 'ccc', 'ddd']