我有一個 df 定義，我正在成功地運行操作。我想計算迭代for循環和矢量化操作之間的差異。我已經閱讀了有關如何使用 timeit 的各種示例，但是當我嘗試使用它們時，出現以下錯誤。我究竟做錯了什么？進口：import h5pyimport pandas as pdimport timeit這個循環有效：for u in df['owner'].unique():    print(u, ': ', len(df[(df['owner'] == u)]), sep = '')但是當我嘗試這樣計時時......：s = """\for u in df['owner'].unique():    print(u, ': ', len(df[(df['owner'] == u)]), sep = '')"""time_iter_1_1_1 = timeit.timeit(s)...它產生這個錯誤：---------------------------------------------------------------------------NameError                                 Traceback (most recent call last)<ipython-input-34-7526e96d565c> in <module>()      3 #     print(u, ': ', len(df[(df['owner'] == u)]), sep = '')""")      4 ----> 5 time_iter_1_1_1 = timeit.timeit(s)~\Anaconda2\envs\py36\lib\timeit.py in timeit(stmt, setup, timer, number, globals)    231            number=default_number, globals=None):    232     """Convenience function to create Timer object and call timeit method."""--> 233     return Timer(stmt, setup, timer, globals).timeit(number)    234     235 def repeat(stmt="pass", setup="pass", timer=default_timer,~\Anaconda2\envs\py36\lib\timeit.py in timeit(self, number)    176         gc.disable()    177         try:--> 178             timing = self.inner(it, self.timer)    179         finally:    180             if gcold:~\Anaconda2\envs\py36\lib\timeit.py in inner(_it, _timer)NameError: name 'df' is not defined當我嘗試這個時......：time_iter_1_1_1 = timeit.timeit("""for u in df['owner'].unique():    print(u, ': ', len(df[(df['owner'] == u)]), sep = '')""")...我收到此錯誤：ERROR:root:An unexpected error occurred while tokenizing inputThe following traceback may be corrupted or invalidThe error message is: ('EOF in multi-line string', (1, 57))...NameError: name 'df' is not defineddf 已定義并正常工作。我怎樣才能解決這個問題？