multithreading - AssertionError when threading in Python

Question

I'm trying to run some simple threading in Python using:

t1 = threading.Thread(analysis("samplequery"))
t1.start()

other code runs in here

t1.join()

Unforunately I'm getting the error:

"AssertionError: group argument must be none for now"

I've never implemented threading in Python before, so I'm a bit unsure as to what's going wrong. Does anyone have any idea what the problem is?

I'm not sure if it's relevant at all, but analysis is a method imported from another file.

I had one follow up query as well. Analysis returns a dictionary, how would I go about assigning that for use in the original method?

Thanks

question from:https://stackoverflow.com/questions/15349997/assertionerror-when-threading-in-python

Answer 1

You want to specify the target keyword parameter instead:

t1 = threading.Thread(target=analysis("samplequery"))

You probably meant to make analysis the run target, but 'samplequery the argument when started:

t1 = threading.Thread(target=analysis, args=("samplequery",))

The first parameter to Thread() is the group argument, and it currently only accepts None as the argument.

From the threading.Thread() documentation:

This constructor should always be called with keyword arguments. Arguments are:

• group should be None; reserved for future extension when a ThreadGroup class is implemented.
• target is the callable object to be invoked by the run() method. Defaults to None, meaning nothing is called.