make output a bit more informative

demos/task-queue.py

@@ -1,20 +1,25 @@
 from multiprocessing import Process, Queue
 
-def f(q):
+def f(q, i):
     while True:
         x = q.get()
         if x is None:
             break
-        print(x**2)
+        print('[{0}] {1}'.format(i, x**2))
 
 q = Queue()
-for i in range(10):
+for i in range(100):
     q.put(i)
 
-# task queue: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+# task queue: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ..., 99]
 
-for i in range(3):
-    q.put(None)
-    p = Process(target=f, args=(q, ))
-    p.start()
+n = 3   # no. of processes
+p = []  # list of processes
+for i in range(n):
+    p.append(Process(target=f, args=(q, i, )))
+    q.put(None)  # add sentinels to signal STOP
+
+# start work on all processes
+for i in range(n):
+    p[i].start()