CODEWITHSUNDEEP
pythonmultithreading
no nein
no nein

Reputation: 711

Threading in python, error when creating threads with specific string input

according to me, weirdest problem that took me forever to figure out because I simply can't fathom what is wrong, anyway here goes:

class pod_spawner():

    def __init__(self):
        self.pod_name="Test"

    def bot_creater(self,bot_nr):
        for i in range(5):
            print(bot_nr + " doing its work")
            time.sleep(2)    

    def add_thread(self):
        threading.Thread(name="Something", target=self.bot_creater, args=("1")).start()

This is perfectly okay, a thread spawns and we are golden however if I change the args input to args=("bot_1") instead of just args=("1"), "it throws me a bot_creater() takes 2 positional arguments but 6 were given" error.

Any and all help would be much appreciated!

Upvotes: 0

Views: 178

Answers (3)

Mohd
Mohd

Reputation: 5613

You can also use a list instead if you have one argument, as the following:

threading.Thread(name="Something", target=self.bot_creater, args=["bot_1"]).start()

Upvotes: 1

TimSC
TimSC

Reputation: 1539

TemporalWolf is right, it takes a tuple. If you just put brackets round a string, it is just taken to be mathematical brackets. If you add a comma, python interprets it as a tuple:

threading.Thread(name="Something", target=self.bot_creater, args=("bot_1",)).start()

Upvotes: 1

TemporalWolf
TemporalWolf

Reputation: 7952

It's converting the string input into a tuple, like so:

tuple(("bob"))
('b', 'o', 'b')

because

>>> type(("bob"))
<type 'str'>

Instead, you want:

>>> tuple(("bob",))
('bob',)

because

>>> type(("bob",))
<type 'tuple'>

Essentially it's ignoring the extra set of parentheses until you give it (element,) which then forces it to interpret it as a tuple of length 1.

Upvotes: 1

Related Questions