TypeError in Threading. function takes x positional argument but y were given

Question

I am working with Python at the moment. I have a start-function, that gets a string from a message. I want to start threads for every message.

The thread at the moment should just print out my message like this:

def startSuggestworker(message):     print(message)  def start():     while True:         response = queue.receive_messages()         try:             message = response.pop()             start_keyword = message.body             t = threading.Thread(target=startSuggestworker, args = (start_keyword))             t.start()             message.delete()         except IndexError:             print("Messages empty")             sleep(150)  start() 

At the moment I get a TypeError and don't understand why. The Exception message is this one:

Exception in thread Thread-1: Traceback (most recent call last):   File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/threading.py", line 914, in _bootstrap_inner     self.run()   File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/threading.py", line 862, in run     self._target(*self._args, **self._kwargs) TypeError: startSuggestworker() takes 1 positional argument but y were given 

*y = length of my String

What am I doing wrong?

Answer 1

The args kwarg of threading.Thread expects an iterable, and each element in that iterable is being passed to the target function.

Since you are providing a string for args:
t = threading.Thread(target=startSuggestworker, args=(start_keyword))

each character is being passed as a separate argument to startSuggestworker.

Instead, you should provide args a tuple:

t = threading.Thread(target=startSuggestworker, args=(start_keyword,)) #                                                                  ^ note the comma