字符串倒序

def reversed(data):
    data = list(data)
    length = len(data)
    mid_length = int(length/2)

    for i in range(mid_length):
        data[i],data[length - i - 1] = data[length - i -1],data[i]
    return ''.join(data)

字符串的倒叙，必须先转换为列表 不然对于for循环里面不支持