初学Python:Python 切片：利用切片操作 实现一个trim()函数 去除字符串首尾的空格

def trim(s):start = 0;end = len(s);while s[start:start+1] == ' ' and start < end:start += 1while s[end-1:end] == ' ' and start < end:end -= 1if start == end:return ''else:return s[start:end]