Python using getattr to call function with variable parameters

This is very simple in Python 3. Here is the example:

class C:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def m(self, x):
        print(f"{self.name} called with param '{x}'")
        return

ci = C("Joe", 10)
print(C)
print(ci)
print(C.m)
print(ci.m)
print(getattr(ci,'m'))
getattr(ci,'m')('arg')

---

<class '__main__.C'>
<__main__.C object at 0x000001AF4025FF28>
<function C.m at 0x000001AF40272598>
<bound method C.m of <__main__.C object at 0x000001AF4025FF28>>
<bound method C.m of <__main__.C object at 0x000001AF4025FF28>>
Joe called with param 'arg'

Note that getattr is from the builtins module, takes in our case the two parameters, the class instance ci and the string representing the name of the function.

We could also define the defult value for the parameter.

def m(self, x=None):
    print(f"{self.name} caled with param '{x}'")
    return

In which case we may call:

getattr(ci,'m')()

You could try something like:

getattr(foo, bar)(*params)

This works if params is a list or a tuple. The elements from params will be unpacked in order:

params=(1, 2)
foo(*params)

is equivalent to:

params=(1, 2)
foo(params[0], params[1])

If there are keyword arguments, you can do that too.

getattr(foo, bar)(*params, **keyword_params)

where keyword_params is a dictionary.

Also, This answer is really independent of getattr. It will work for any function/method.