Pass keyword arguments to target function in Python threading.Thread

Question

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.

You don't need to use specify the names of the arguments, you can use a plain tuple: t = threading.Thread(target=f, args=(1,2,)) — bonh
– bonh, Commented May 12, 2017 at 15:42

vladosaurus · Accepted Answer · 2015-09-23 08:18:46Z

152

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'})

edited Sep 23, 2015 at 8:18

answered Sep 22, 2015 at 13:15

vladosaurus

1,8381 gold badge16 silver badges18 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

SuperBiasedMan Over a year ago

Please consider editing your post to add more explanation about what your code does and why it will solve the problem. An answer that mostly just contains code (even if it's working) usually wont help the OP to understand their problem.

Jerry Hu Over a year ago

I have no problem with vladosaurus's answer as it is. Longer isn't always more helpful; being concise is. In this case it saves my day within seconds.

Daniel · Accepted Answer · 2017-07-04 22:57:30Z

16

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()

answered Jul 4, 2017 at 22:57

Daniel

3,4845 gold badges29 silver badges35 bronze badges

Comments

President James K. Polk · Accepted Answer · 2024-04-11 23:02:53Z

1

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

edited Apr 11, 2024 at 23:02

President James K. Polk

42.3k34 gold badges113 silver badges149 bronze badges

answered Jun 18, 2015 at 10:47

f43d65

2,30213 silver badges15 bronze badges

2 Comments

glglgl Over a year ago

Surely not. ITYM {'x': 1, 'y': 2}, which is a huge difference.

President James K. Polk Over a year ago

@ LoganSonOfGrim: Please do not add commentary to content that you edit explaining your edit.

Collectives™ on Stack Overflow

Pass keyword arguments to target function in Python threading.Thread

3 Answers 3

2 Comments

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related