Python using getattr to call function with variable parameters
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.
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}'") returnci = 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')()
A maybe more readable way, which is better for handling exceptions:
class foo: def method_xy(self, *args, **kwargs): print(f'args:{args}, kwargs:{kwargs}')bar = 'method_xy'xi = foo()try: func_name = getattr(xi, bar)except AttributeError: # handle missing method passargs = ['bla1', 'bla2']kwargs = {'a1': 1, 'a2': 2}try: result = func_name(*args, **kwargs)except TypeError: # handle Problems with arguments pass