python 切片slice

實現php中trim函數，去掉字符串收尾的空格

def trim(s):

    if s[0:1] != '' and s[-1:] != '':

        return s

    elif s[0:1] != '':

        return trim(s[1:])

    else:

        return trim(s[:-1])

print(trim('   jyl test   ')