Referencing a static attribute as initialisation for another static attribute in python 3

Question

I'm a newby to python so please excuse the nomenclature stolen from other languages. I have a class containing a "static" attribute (a list) and a static method. I want to initialise the param to contain just a reference to the method:

class LogFilter(object):

    @staticmethod
    def _process_friendly_time(params):
        # process params
        pass

    param_processors = [
        LogFilter._process_friendly_time
    ]

# Later
for processor in LogFilter.param_processors:
    processor(params)

This code causes an error

NameError: name 'LogFilter' is not defined`.

But if I replace LogFilter._process_friendly_time with just _process_friendly_time then I later get an error...

TypeError: 'staticmethod' object is not callable

Is there a syntax that will let me do this, or must I move the static method outside the class?

khelwood · Accepted Answer · 2019-03-27 11:34:57Z

1

You can't refer to LogFilter._process_friendly_time at a point before LogFilter has been defined. At the point where you are currently declaring param_processors, you are midway through the definition of LogFilter: the definition is not yet complete.

You can move the field declaration to after the class.

class LogFilter:
    @staticmethod
    def _process_friendly_time(params):
        # process params
        pass

LogFilter.param_processors = [
    LogFilter._process_friendly_time
]

But consider whether you are actually getting any benefit out of using a static method. People often use them out of habit from other languages, but there is no benefit in this case: a standalone function would make more sense.

answered Mar 27, 2019 at 11:34

khelwood

59.7k14 gold badges91 silver badges116 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Referencing a static attribute as initialisation for another static attribute in python 3

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related