Apply list of functions on an object in Python

Question

Is there any clean way to apply a list of functions on an object in Python without lambda or list comprehensions? Like the Haskell expression:

map ($ obj) [foo1,foo2]

Example with lambda in Python:

response = map(lambda foo:foo(obj),[foo1,foo2]) #fooX:object->Bool

Is it extendable to class functions?

Perhaps something from operator or itertools?

Answer 1

You could always just create a function to take care of it for you:

def map_funcs(obj, func_list):
    return [func(obj) for func in func_list]

    # I was under the impression that the OP wanted to compose the functions,
    # i.e. f3(f2(f1(f0(obj))), for which the line below is applicable:
    # return reduce(lambda o, func: func(o), func_list, obj)


map_funcs(it, [Buy, Use, Break, Fix])

Answer 2

I think this should fit your 'functional' criteria, To answer your question, I don't think there is a clean way and you should just acclimatize to list comprehensions.

As suggested by @J.F.Sebastian

>>> from operator import methodcaller
>>> funcs = (lambda x: x + 1, lambda x: x + 2)
>>> obj = 5
>>> list(map(methodcaller('__call__', obj), funcs))
[6, 7]

Here is a crazy way of doing it:

>>> from itertools import starmap, repeat
>>> from types import FunctionType
>>> funcs = (lambda x: x + 1, lambda x: x + 2)
>>> obj = 5
>>> list(starmap(FunctionType.__call__, zip(funcs, repeat(obj))))
[6, 7]

As suggested by @AleksiTorhamo

>>> from itertools import repeat
>>> from types import FunctionType
>>> obj = 5
>>> funcs = (lambda x: x + 1, lambda x: x + 2)
>>> list(map(FunctionType.__call__, funcs, repeat(obj)))
[6, 7]