Using function's name to call the function inside a class in Python

Question

How can I call the function John inside function name_dispatcher, by its name == str(B) only and without using John ?

class A:
    def name_dispatcher(self, person):
        if person == "John":
           self.John()
        elif person == "Ben":
           self.Ben()
    def John(self):
        print("I am john")
    def Ben(self):
        print("I am Ben")
A("John").C()

Because I want to aviod something in ‘def name_dispatcher’ when the number of parameters get largers, if I can call the function by its name, I don’t need to add the additional if and elif condition as def name_dispatcher.
Will the method better than if-else? Or is a there any readable and efficient method to do so?

Asked By: tung

||

Source

Answer 1

As already indicated in the comments to the original question, you need to access the methods on the instance. For instance:

class A:
    def C(self, person):
        try:
            getattr(self, person)()
        except AttributeError:
            print(f'there is no method for `{person}` in the A class')
        
    def John(self):
        print("I am john")
        
    def Ben(self):
        print("I am Ben")
        
A().C('John')
I am john

A().C('Daniel')
there is no method for `Daniel` in the A class

Although it is legit to wonder why you would want to implement such a programming pattern, getattr is there exactly for similar purposes. Still, I agree with the comments that without a better explanation, this is a programming pattern one should avoid.

Answered By: deponovo

Using function's name to call the function inside a class in Python

Question:

Answers: