python基本语法3.6--字符串的翻转

def reverse(str_list, start, end):
    while start < end:
        str_list[start], str_list[end] = str_list[end], str_list[start]
        start += 1
        end -= 1

sentence = ' I love Jinchenn'
str_list = list(sentence)

i = 0
while i < len(str_list):
    if str_list[i] != ' ':
        start = i
        end = i + 1
        while (end < len(str_list)) and str_list[end] != ' ':
            end += 1
        i = end
        reverse(str_list,start,end-1)
    else:
        i += 1


str_list.reverse()
print(''.join(str_list))