py UnboundLocalError:赋值前引用的局部变量“start\U time”

Question

编辑。。 完全回溯：

Traceback (most recent call last):
  File "dscli.py", line 36, in <module>
    main()
  File "dscli.py", line 31, in main
    instance_StreamingDownloader.download_all()
  File "file.py", line 283, in download_all
    time_first_frame_last_segment = self.get_time_saved_segment(crrt_segment - 1)
  File "file.py", line 239, in get_time_saved_segment
    return(start_time)
UnboundLocalError: local variable 'start_time' referenced before assignment

code here

它只获取第一个段，然后返回错误

我如何解决这个问题

来自github的代码

Answer 1

如果不满足条件，则：

    Traceback (most recent call last):
  File "dscli.py", line 36, in <module>
    main()
  File "dscli.py", line 31, in main
    instance_StreamingDownloader.download_all()
  File "file.py", line 286, in download_all
    lenght_ahead_buffered = time_first_frame_last_segment - time_if_streaming + random_perturbation
TypeError: unsupported operand type(s) for -: 'NoneType' and 'float'

第280-286行：

while continue_download:
                time_first_frame_last_segment = self.get_time_saved_segment(crrt_segment - 1)

                time_if_streaming = time.time() - init_time
                random_perturbation = random.gauss(0, self.random_time)
                if self.verbose > 1:
                    print("time in video if streaming: " + str(time_if_streaming))

Answer 2

答案很简单- 该条件允许在脚本运行期间未定义开始时间的某些情况 因此，由于没有定义，它失败了

Answer 3

start_time是在for循环中的if语句中定义的

如果不进入循环，或者不满足条件，该怎么办？函数应该返回什么

start_time需要在任何控制流子句之外的函数体中初始化（例如start_time = 0 / None / False），以便始终定义它，因此您可以始终返回它