Python 反转

#!/usr/bin/env python3

nums = [2, 7, 8, 9, 1, 0]
nums.reverse()

print(nums)

rev_nums = nums[::-1]
print(rev_nums)

$ ./reverse_list.py
[0, 1, 9, 8, 7, 2]

#!/usr/bin/env python3

words = ['forest', 'wood', 'sky', 'rock']

for word in reversed(words):
    print(word)

word = 'forest'

for e in reversed(word):
    print(e, end=' ')

print()

for e in reversed(range(1, 10, 2)):
    print(e)

$ ./reversed_fun.py
rock
sky
wood
forest
t s e r o f
9
7
5
3
1

#!/usr/bin/env python3

def reverse_string(word):

    rev = ''
    n = len(word)

    while n > 0:
        n -= 1                 
        rev += word[n] 
    return rev

word = 'forest'

print(reverse_string('forest'))

def reverse_string(word):

    rev = ''
    n = len(word)

    while n > 0:
        n -= 1                 
        rev += word[n] 
    return rev

#!/usr/bin/env python3

class Vowels(object):

    def __init__(self):

        self.vowels = ['a', 'e', 'i', 'o', 'u', 'y']

    def __len__(self):
        return len(self.vowels)

    def __getitem__(self, e):
        return self.vowels[e]

    def __reversed__(self):
        for e in self.vowels[::-1]:
            yield elem        

vowels = Vowels()

print('normal order:')
for vowel in vowels:
    print(vowel, end=' ')

print()

print('reversed order:')
for vowel in reversed(vowels):
    print(vowel, end=' ')    

print()   

$ ./reversed_magic.py
normal order:
a e i o u y
reversed order:
y u o i e a