How to pass parameters to function via variable?

Question

i am executing function in separate thread and want to pass arguments via queue. So function should be idealy able to accept all variables encapsulated in one variable

something like:

v = ('arg1', kwarg1='val1', kwarg2='val2')

def print_arg(*args, **kwargs):
    print('args:{}\nkwargs:{}'.format(args, kwargs))

print_arg(v)

Is there any simple way how to achieve this?

Thanks

Answer 1

One way for you to do this may be to build the queue in your main thread and pass it as an argument to the thread you create:

q = queue.Queue()   
thread1 = threading.Thread(target=main_function,args(q,other_args)) 

In either thread, use the put method to add information to the queue as strings:

q.put(str(important_variable))

Retrieve this information from the queue with the get method

important_variable = q.get()

If passing multiple variables or information, use multiple queues or structure what you put into the queue so that you know what it is you're pulling out of the queue.

Answer 2

While yes, you can store all arguments in a single variable, you still need to store the positional arguments separately from the keyword arguments. There is no data structure that can function as a sequence and a mapping at the same time.

Here's one way to do it:

v = ['arg1'], {'kwarg1': 'val1', 'kwarg2': 'val2'}
print_arg(*v[0], **v[1])

This is a bit tedious and hard to read, so we can encapsulate the whole thing in a class:

class ArgumentBundle:
    def __init__(self, *args, **kwargs):
        self.args = args
        self.kwargs = kwargs

    def call(self, function):
        return function(*self.args, **self.kwargs)

v = ArgumentBundle('arg1', kwarg1='val1', kwarg2='val2')
v.call(print_arg)