python - 当向 uuid.UUID() 提供无效参数时会发生什么？

Question

会抛出异常吗？ UUID() 是否会悄无声息地失败？是否有任何情况下“myStatus”来自

myStatus = True
myUUID = uuid.UUID( someWeirdValue )
if myUUID == None:
    myStatus = False

是否等于 False？

Answer 1

UUID() 构造函数会引发 TypeError 或 ValueError，具体取决于传入的内容。

不传递任何 hex、bytes、bytes_le、fields 或 int 选项引发 TypeError，传入无效值引发 ValueError:

>>> uuid.UUID()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/uuid.py", line 129, in __init__
    raise TypeError('need one of hex, bytes, bytes_le, fields, or int')
TypeError: need one of hex, bytes, bytes_le, fields, or int
>>> uuid.UUID('abcd')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/uuid.py", line 134, in __init__
    raise ValueError('badly formed hexadecimal UUID string')
ValueError: badly formed hexadecimal UUID string
>>> uuid.UUID(bytes='abcd')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/uuid.py", line 144, in __init__
    raise ValueError('bytes is not a 16-char string')
ValueError: bytes is not a 16-char string

等等

它不会默默地失败。它肯定永远不会返回 None。 myUUID 设置为 UUID 实例，或者引发异常。