CODEWITHSUNDEEP
pythonmultithreadingpython-2.7thread-safety
ρss
ρss

Reputation: 5315

Reading the results from an infinite loop using threads in python

I am currently working with python v.2.7 on windows 8.

My programme is using threads. The threads execute a method named as getData() for infinite time that does the following:

The compareValues() does the following:

I save the results of these threads to a list named as myList and then finally print this myList.

Problem: As the getData() is looping for infinite time. How can I access the myList for retrieving the results? What would be a good approach in this case. If you remove the while True: then the programm works fine.

Code:

import time
from random import randrange
import threading

myList = []
def getData(i):
   while True:
        print "Sleep for %d"%i
        time.sleep(i)
        data = compareValues()
        for d in list(data):
            myList.append(d)

def compareValues():
        number = randrange(10)
        name = threading.current_thread().name
        if number >= 5:
             yield "%s: Greater than or equal to 5: %d  "%(name, number)
        else:
             yield "%s: Less than 5: %d  "%(name, number)

threadList = []
wait = randrange(10)+1
t = threading.Thread(name = 'First-Thread', target = getData, args=(wait,))
threadList.append(t)
t.start()
wait = randrange(3)+1
t = threading.Thread(name = 'Second-Thread', target = getData, args=(wait,))
threadList.append(t)
t.start()
for t in threadList:
    t.join()
print "The final list"
print myList

Thank you for your time.

Upvotes: 1

Views: 332

Answers (1)

Javier
Javier

Reputation: 1087

I see a couple of inconsistencies that may help to make the code look a little bit more clear. For instance:

  1. compareValues() should return 'The result in string Format......' and not yield. Am I right? Because this function is going to evaluate only one value at a time.

  2. getData() should look like:

    def getData(i):
    while True:
        print "Sleep for %d"%i
        time.sleep(i)
        myList.append(compareValues())

Exactly for the same reason as I said in the previous point.

P.S.: I don't know why the code is not formatting properly. Sorry... :-(

I hope it helps!

Upvotes: 1

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