How to find all possible combinations of parameters and funtions

Question

info & requirements:

1. Two lists are given, a list of variables and a list of functions, no function requires more parameters then there are variables in the variable list.
2. All possible combinations of input variables must be found for every function in the functions list. that means from 0 -> len(variables)
3. There is no guarantee that the function will accept the parameters.
4. No edits can be made in the functions in the functions list, they can only be called.

When trying to solve this myself I found a solution that could handle functions with 2 parameters, but I don't know how to make it dynamic so it can scale to infinite parameters

#  test input list
# functions = [test_method1, test_method2]
# variables = [1, 2, 3, 4, 5]

for f in functions: 
    for v in variables:  # loop all conditions
        try:  # checks if combination throws error
            f(v)
        except TypeError as a:  # if amount of parameters is > 1
            for v2 in variables:  # loop all conditions
                try:  # tries combination
                    f(v, v2)

                except TypeError as e:  

The above-shown code is not part of the solution, it's just my best try and is just for inspiration.

The result should be that all functions have tried to run with all possible combination of variables as parameters.

Answer 1

You can use itertools to get all subsets and create recursion function like this:

from itertools import combinations

def test_method1(x):
    print("METHOD 1 :", x)

def test_method2(x, y):
    print("METHOD 2 :", x, y)

functions = [test_method1, test_method2]
variables = [1, 2, 3, 4, 5]

def run_all_methods(input_num):
    if input_num > len(variables):
        return
    for item in functions:
        try:
            for var_list in set(combinations(variables * input_num,input_num)):
                item(*list(var_list))
            input_num += 1
        except TypeError as a:
            run_all_methods(input_num+1)

run_all_methods(1)

OUT:
===
METHOD 1 : 2
METHOD 1 : 5
METHOD 1 : 3
METHOD 1 : 1
METHOD 1 : 4
METHOD 2 : 1 3
METHOD 2 : 2 1
METHOD 2 : 5 1
METHOD 2 : 2 5
METHOD 2 : 1 2
METHOD 2 : 3 3
METHOD 2 : 5 5
METHOD 2 : 4 4
METHOD 2 : 1 5
METHOD 2 : 2 2
METHOD 2 : 3 4
METHOD 2 : 4 1
METHOD 2 : 1 1
METHOD 2 : 3 2
METHOD 2 : 5 4
METHOD 2 : 4 5
METHOD 2 : 1 4
METHOD 2 : 2 3
METHOD 2 : 4 2
METHOD 2 : 3 5
METHOD 2 : 5 3
METHOD 2 : 3 1
METHOD 2 : 4 3
METHOD 2 : 5 2
METHOD 2 : 2 4

UPDATE:

1. cast combinations(variables,input_num) to set to avoid duplication.
2. You must add input_num += 1 after for

3. The * can also be used for unpacking the containers. Its principles are similar to “For using the variadic arguments” above. The easiest example is that we have data in the form of a list, tuple or dict, and a function takes variable arguments.

4. variables * input_num can make the duplicated item exp :

a ==> [1, 2]
combinations(a, 2) => (1, 2)

a * 2 ==> [1, 2, 1, 2]
combinations(b, 2) => (1, 2)
                      (1, 1)
                      (1, 2)
                      (2, 1)
                      (2, 2)
                      (1, 2)

set(combinations(b, 2)) => (1, 2)
                           (1, 1)
                           (2, 1)
                           (2, 2)

Read Understanding the asterisk(*) of Python