Passing a class (not instance) in python?

Question

Relatively new to python, coming from C#, so bear with me :)

Basically I got a ton of "nearly-duplicated" SQLAlchemy code that looks like so ...

def method1():    
    dbObj1 = Class1.query.filter_by(id=search_id).first()
    [a bunch of operations on this object]

....

def method2():
    dbObj2 = Class2.query.filter_by(id=search_id).first()
    [the same operations on this object]

The operations performed on these objects are the same and access properties that exist in both these classes. In C# or Java I'd solve that by having some sort of base class and/or using generics. However I have no clue how one would solve such duplication problems in Python.

Is there anything similar to generics? Or maybe that SQLAlchemy query could be changed in some way so these occurrences can be deduplicated?

Thanks for any inputs :)

EDIT: made the example a little more clear

Classes are, themselves, objects so you can do for class_name in (Class1, Class2): class_name.query.filter..... — FiddleStix
– FiddleStix, Commented Feb 10, 2020 at 10:12
@FiddleStix well it's in different methods, not right after each other :D But I guess that also means I could have something like doOperationsOn(Class1), right? — FrankyBoy
– FrankyBoy, Commented Feb 10, 2020 at 10:14

Jina Jita · Accepted Answer · 2020-02-10 10:14:27Z

1

You can actually just pass the class like this:

class A:
        def foo(self):
                return "foo"

class B: 
        def foo(self):
                return "bar"

def do_something(c):
        e = c()
        print(e.foo())


do_something(A)
do_something(B)

answered Feb 10, 2020 at 10:14

Jina Jita

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3 Comments

Serge Ballesta Over a year ago

Passing the class is fine, but OP wants to use a class (or static) attribute later, so no need of creating an instance.

FrankyBoy Over a year ago

Didn't know that, that looks exactly like what I need. @SergeBallesta I guess it was just for examples sake to show creation of an instance with the passed class ;)

FrankyBoy Over a year ago

@SergeBallesta I'm aware ... but there is a minimum time limit before you can accept an answer ... so I got to sit that one out ;)

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