Python input and output threading

Question

I want to create a python script that prints out messages from one thread, while still waiting for you to input on another. Is this possible? And if so, how?

System: Windows 7

Language: Python 2.7

I have tried this (modified from a different question):

import threading
import time

def message_loop():
    while True:
        time.sleep(1)
        print "Hello World"

thread = threading.Thread(target = message_loop)
thread.start()

while True:
    input = raw_input("Prompt> ")

But what happens is: the program waits until I have finished inputting before it outputs Hello World.

Adding to Coffee's question, what have you read? Did you look at the Python documentation? — Codie CodeMonkey
– Codie CodeMonkey, Commented Jul 27, 2013 at 4:16
I have read the documentation, and I have tried code done by others, but what happens is the code whats for me to press enter and then it outputs — lewisjb
– lewisjb, Commented Jul 27, 2013 at 4:29

icktoofay · Accepted Answer · 2013-07-27 04:25:25Z

2

It's absolutely possible. If you have a function that prints output (let's call it print_output) you can start it up in a different thread using the threading module:

>>> import threading
>>> my_thread = threading.Thread(target=print_output)
>>> my_thread.start()

You should now start getting your output. You can then run the input bit on the main thread. You could also run it in a new thread, but there are some advantages to running input in the main thread.

answered Jul 27, 2013 at 4:25

icktoofay

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2 Comments

lewisjb Over a year ago

That just tells me how to thread, it doesn't do what I want it to though

icktoofay Over a year ago

@Pyro: I can't reproduce your problem. It works fine for me, although I'm on 2.6 rather than 2.7 and I'm not on Windows.

alcoder · Accepted Answer · 2019-05-13 18:33:04Z

2

This works for me. The code prints message before you input 'q'

import threading
import time


def run_thread():
    while True:
        print('thread running')
        time.sleep(2)
        global stop_threads
        if stop_threads:
            break


stop_threads = False
t1 = threading.Thread(target=run_thread)
t1.start()
time.sleep(0.5)

q = ''
while q != 'q':
    q = input()

stop_threads = True
t1.join()
print('finish')

answered May 13, 2019 at 18:33

alcoder

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