python核心编程第六章课后题自己做的答案

 1 'Take a string and remove all leading and trailing whitespace' 2  3 def newStrip(str): 4     'delete blanks around a string' 5     _end = len(str) 6     _start = 0 7      8     # delete the blanks at the beginning of the string 9     for i in range(_end):10         if str[i] != ' ':11             _start = i12             break              13     else:14         PRint 'invalid: The string is a blank string.'     # if the string is a 15         _blank = True                                      # blank string16         17     18     # delete the blanks in the end of the string19     for i in range(-1, _start - _end, -1):20         if str[i] != ' ':21             _end = _end + i22             break      23     if not _blank:24         print '-' + str[_start: _end] + '-'   # print '-' make sure the function work25 26 # test27 if __name__ == '__main__':28     newStrip(raw_input('Enter a string: '))