方法一：求首位非空的位置 **def strip_version2(s): begin = 0 end = -1 length = len(s) for i in range(length): if s[i] != ' ': begin = i break j = length-1 while j >= begin and s[j] == ' ': j -= 1 pass end = j

return s[begin:end+1]
**

方法二：利用递归

def trim(s):

if s == '':

return s

if s[0] == ' ':

return trim(s[1:])

if s[-1] == ' ':

return trim(s[:-1])

else:

return s