Pass keyword arguments to target function in Python threading.Thread

xennygrimmato picture xennygrimmato · Jun 18, 2015 · Viewed 46.9k times · Source

I want to pass named arguments to the target function, while creating a Thread object.

Following is the code that I have written:

import threading

def f(x=None, y=None):
    print x,y

t = threading.Thread(target=f, args=(x=1,y=2,))
t.start()

I get a syntax error for "x=1", in Line 6. I want to know how I can pass keyword arguments to the target function.

Answer

vladosaurus picture vladosaurus · Sep 22, 2015
t = threading.Thread(target=f, kwargs={'x': 1,'y': 2})

this will pass a dictionary with the keyword arguments' names as keys and argument values as values in the dictionary. the other answer above won't work, because the "x" and "y" are undefined in that scope.

another example, this time with multiprocessing, passing both positional and keyword arguments:

the function used being:

def f(x, y, kw1=10, kw2='1'):
    pass

and then when called using multiprocessing:

p = multiprocessing.Process(target=f, args=('a1', 2,), kwargs={'kw1': 1, 'kw2': '2'})