On 2024-06-28 18:08:54 +0200, Ulrich Goebel via Python-list wrote: > a class can have methods, and it can have attributes, which can hold a > function. Both is well known, of course. > > My question: Is there any difference? > > The code snipped shows that both do what they should do. But __dict__ > includes just the method,
The other way around: It includes only the attributes, not the methods.
> while dir detects the method and the
> attribute holding a function. My be that is the only difference?
>
>
> class MyClass:
> def __init__(self):
> functionAttribute = None
>
> def method(self):
> print("I'm a method")
>
> def function():
> print("I'm a function passed to an attribute")
Here is the other main difference: The object is not passed implicitely
to the function. You have no way to access mc here.
You can create a method on the fly with types.MethodType:
import types
mc.functionAttribute = types.MethodType(function, mc)
> By the way: in my usecase I want to pass different functions to
> different instances of MyClass. It is in the context of a database app
> where I build Getters for database data and pass one Getter per
> instance.
Or in this case, since each function is specific to one instance, you
could just use a closure to capture the object. But that might be
confusing to any future maintainers (e.g. yourself in 6 months), if the
method doesn't actually behave like a method.
hp
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| | | h...@hjp.at | -- Charles Stross, "Creative writing
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