Pass keyword arguments to target function in Python threading.Thread

问题

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.

回答1:

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'})

回答2:

You can also just pass a dictionary straight up to kwargs:

import threading

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

my_dict = {'x':1, 'y':2}
t = threading.Thread(target=f, kwargs=my_dict)
t.start()

回答3:

Try to replace args with kwargs={x: 1, y: 2}.

来源：https://stackoverflow.com/questions/30913201/pass-keyword-arguments-to-target-function-in-python-threading-thread