Is there a way in Python to return a value via an output parameter?

Question

Some languages have the feature to return values using parameters also like C#. Let’s take a look at an example:

class OutClass
{
    static void OutMethod(o         


        

Answer 1

You can do that with mutable objects, but in most cases it does not make sense because you can return multiple values (or a dictionary if you want to change a function's return value without breaking existing calls to it).

I can only think of one case where you might need it - that is threading, or more exactly, passing a value between threads.

def outer():
    class ReturnValue:
        val = None
    ret = ReturnValue()
    def t():
        # ret = 5 won't work obviously because that will set
        # the local name "ret" in the "t" function. But you
        # can change the attributes of "ret":
        ret.val = 5

    threading.Thread(target = t).start()

    # Later, you can get the return value out of "ret.val" in the outer function