Is there a way to call specific classes based on a variable?

December 13, 2022

I want a program to call a specific class based on a parameter/variable value. However, I don’t want to use any clunky if-statements. My first thought was to use the globals() function, but I couldn’t get it to work. Here’s an example:

class SomeClass:
    def __init__():
        print("Hello, world!")

class OtherClass:
    def runClass(className):
        # Call class based on variable className

The reason I want to do this is because there is a wide variety of classes may need to be called, and so just piling up if-statements in my code won’t do it. Any help would be greatly appreciated. Thanks!

>Solution :

Here’s how you can call a class via globals

class SomeClass:
    def __init__(self):
        print("Hello, world!")

    def __call__(self):
        return "SomeClass called"

class OtherClass:
    def runClass(self, className):
        globals()[className]()()
        
o = OtherClass()
result = o.runClass("SomeClass")
print(result)

Notice, I am instantiating and then calling it via the __call__ special method, which is the closest match to your description I could think of.