pythonargumentsmutual-exclusion

How do I make a Python function with mutually exclusive arguments?


I have a Python class which needs to accept one of two mutually exclusive arguments. If the arguments are not exclusive, (ie: if both or neither are given), an error should be raised.

class OrgLocation:
    def __init__(self, location_num=None, location_path=None):
        """location_num & location_path are mutually exclusive"""

In most scenarios, the best option would be to make two separate classes. However, I am working with an external API which requires these two attributes to be mutually exclusive.

Request:

<OrgLocation LocationPathName="ROOT/BU/DIV/SL/DEPT/JOB" LocationNum="1234"/>

Response:

<Error Message="Use either LocationNum or LocationPathName but not both." ErrorCode="1186">

Similar questions seem to indicate that argparse can be used for mutually exclusive arguments in command-line interfaces, but I'm unsure how to apply this to a class constructor

How can I create a Python function with mutually exclusive arguments?


Solution

  • You might want to create a test in the __init__ method but a better question might be... Why?

    if location_num is not None and location_path is not None:
        raise TheseParametersAreMutuallyExclusiveError()
    

    Why would you make a class that has multiple purposes? Why not create separate classes?