翻转字符串的几种方法

#1.切片，步长为-1
a='asdfghjkl'
print(a[::-1])
#2.用列表的reverse方法,最后把列表拼接成字符串
a='asdfghjkl'
a=list(a)
a.reverse()
b=''.join(a)
print(b)
#3.逆序遍历列表，最后在拼接成字符串
a='asdfghjkl'
b=[]
for i in range(len(a)-1,-1,-1):
    b.append(a[i])
b=''.join(b)
print(b)
#4.逆序遍历字符串
a='asdfghjkl'
b=''
for i in reversed(a):
    b=b+i
print(b)