python in reverse order traversal

1, the list itself reverse

= A [. 1,. 3,. 7,. 5, 2,. 6 ] 
a.reverse ()   # carried out in reverse order in the list itself, does not return a new value 
Print (A) 

# Output A: 
# [. 6, 2,. 5,. 7, 3, 1]

 

2, returns a copy

= A [. 1,. 3,. 7,. 5, 2,. 6 ] 
B = A [:: -. 1]   # return the new data, it is necessary to receive the variable 
Print (B) 

# output B: 
# [. 6, 2,. 5, 7, 3, 1]

3, iterator that generates

A = [. 1,. 3,. 7,. 5, 2,. 6 ] 
B = the reversed (A)   # iterator that generates 
Print (B)
 # output B: 
# <list_reverseiterator AT 0x21a161a8ba8> 

# iterator need to iterate extraction 
for X in B:
     Print (X)
 # output X: 
6 
2 
5 
7 
3 
1 # or convert a list generator list (B)
 # output: 
# [6, 2, 5, 7, 3, 1]

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4, generates the inverted index using a range

a = [1, 3, 7, 5, 2, 6]

for i in range(len(a)-1, -1, -1):
    print(a[i])
# 输出：
6
2
5
7
3
1

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