随机改变被调用函数的顺序

Question

I have a function whose outline is given below. In main() , I want to return the returned values of one of the functions but I want to choose it randomly. As of now, it checks func1 first and proceeds only if func1 is some_val . I want to be able to check func2 first sometimes as well.

I realize that I could call both functions, create a list with the outcomes, and randomly shuffle the list but both func1 and func2 are quite a bit involved, so performance is an issue.

Is there a clean way to do it?

def func1():
    
    ... do things
    
    return val

def func2():
    
    ... do things
    
    return val



def main():
    
    if func1() is not some_val:
        return func1()
    
    elif func2() is not some_val:
        return func2()
    
    else:
        return None

Answer 1

Shuffle the list of functions, then iterate over that list, calling them one at a time.

def main():
    functions = [func1, func2, func3]
    random.shuffle(functions)

    for f in functions:
        if (rv := f()) is not some_val:
            return rv

Note that this does require each function to have the same signature (and take the same arguments), but it is trivial to create a list of zero-argument functions that call the "real" functions with the appropriate arguments. Eg,

functions = [lambda: func1(x, y), lambda: func2(z, "hi", 3.14)]

Answer 2

from random import shuffle

def main(list_of_functions=[func1, func2], *args, **kwargs):
    shuffle(list_of_functions)
    outcomes = []
    for func in list_of_functions:
        outcomes.append(func(*args, **kwargs))
    return outcomes

main()

Assuming func1() returns "hello" and func2() returns "world" ...

>>> main()
["hello", "world"]
>>> main()
["world", "hello"]
>>> main()
["world", "hello"]

Pretty simple. That's all you need to do. Functions can be stored as variables like this:

>>> def otherFunc():
...     print("hi")
...
>>> otherFunc()
hi
>>> someFunc = otherFunc
>>> someFunc()
hi

Answer 3

import random

def f1():
    print(1)

def f2():
    print(2)

def f3():
    print(3)

listf=[f1,f2,f3]

for i in range(10):
    random_index = random.randrange(0,len(listf))
    listf[random_index]()

Result:

2
2
1
2
1
3
2
3
3
2