字符串倒序

1.将一个字符串倒序

def str_reverse(s):
    return s[::-1]

def func2(s):
    list1 = list(s)
    list1.reverse()
    return ''.join(list1)

def func3(s):
    list1 = []
    for i in range(len(s)-1,-1,-1):
        list1.append(s[i])
    return ''.join(list1)

def func4(s):
    if len(s)<=1:
        return s
    return s[-1] + func4(s[:-1])

def rever(st):
    b = len(st) >> 1
    d = list(st)
    c = len(st)
    for i in range(b):
        d[i], d[c - 1 - i] = d[c - 1 - i], d[i]
    return ''.join(d)

a = '123321'
b = '12321'
print(rever(a)) # 123321
print(rever(b)) # 12321