python中字符串数组如何逆序排列

>>> arr = [1,2,3,4,3,4]
>>> print (arr[::-1])
[4, 3, 4, 3, 2, 1]

>>> arr = [1,2,3,4,3,4]
>>> arr.reverse()
>>> print (arr)
[4, 3, 4, 3, 2, 1]

arr = [1,2,3,4,3,4]
reversed_arr = [] 
for i in reversed(arr):
 reversed_arr.append(i)
print (reversed_arr)
[4, 3, 4, 3, 2, 1]