How to determine enumeration values ​​that are functions?

I have a situation where I need to enforce and provide the user with the option of one of several select functions that will be passed as an argument to another function:

I really want to achieve something like the following:

from enum import Enum

#Trivial Function 1
def functionA():
    pass

#Trivial Function 2
def functionB():
    pass

#This is not allowed (as far as i can tell the values should be integers)
#But pseudocode for what I am after
class AvailableFunctions(Enum):
    OptionA = functionA
    OptionB = functionB

So, you can do the following:

def myUserFunction(theFunction = AvailableFunctions.OptionA):
   #Type Check
   assert isinstance(theFunction,AvailableFunctions) 

   #Execute the actual function held as value in the enum or equivalent
   return theFunction.value() 
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1 answer

Your guess is wrong . Values ​​can be arbitrary; they are not limited to integers. From the documentation :

. ( API), . , . , .

, !

In [1]: from enum import Enum

In [2]: def f(self, *args):
   ...:     pass
   ...: 

In [3]: class MyEnum(Enum):
   ...:     a = f
   ...:     def b(self, *args):
   ...:         print(self, args)
   ...:         

In [4]: list(MyEnum)  # it has no values
Out[4]: []

In [5]: MyEnum.a
Out[5]: <function __main__.f>

In [6]: MyEnum.b
Out[6]: <function __main__.MyEnum.b>

, functools.partial:

from functools import partial

class MyEnum(Enum):
    OptionA = partial(functionA)
    OptionB = partial(functionB)

:

In [7]: from functools import partial

In [8]: class MyEnum2(Enum):
   ...:     a = partial(f)
   ...:     def b(self, *args):
   ...:         print(self, args)
   ...:         

In [9]: list(MyEnum2)
Out[9]: [<MyEnum2.a: functools.partial(<function f at 0x7f4130f9aae8>)>]

In [10]: MyEnum2.a
Out[10]: <MyEnum2.a: functools.partial(<function f at 0x7f4130f9aae8>)>

-:

In [13]: class Wrapper:
    ...:     def __init__(self, f):
    ...:         self.f = f
    ...:     def __call__(self, *args, **kwargs):
    ...:         return self.f(*args, **kwargs)
    ...:     

In [14]: class MyEnum3(Enum):
    ...:     a = Wrapper(f)
    ...:     

In [15]: list(MyEnum3)
Out[15]: [<MyEnum3.a: <__main__.Wrapper object at 0x7f413075b358>>]

: , __call__ , :

In [1]: from enum import Enum

In [2]: from functools import partial

In [3]: def f(*args):
   ...:     print(args)
   ...:     

In [4]: class MyEnum(Enum):
   ...:     a = partial(f)
   ...:     def __call__(self, *args):
   ...:         self.value(*args)
   ...:         

In [5]: MyEnum.a(1,2,3)   # no need for MyEnum.a.value(1,2,3)
(1, 2, 3)
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Source: https://habr.com/ru/post/1659383/


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