ZeroMQ Pub/Sub simplest example is not working - What am I doing wrong?

Question

Following the example in zmq documentation, here is my take with minor changes.

publisher.py

import zmq
import random
import time

port = "5556"

context = zmq.Context()
socket = context.socket(zmq.PUB)
socket.bind("tcp://127.0.0.1:%s" % port)


while True:
    topic = random.randrange(9999,10005)
    messagedata = random.randrange(1,215) - 80
    print "%d %d" % (topic, messagedata)
    socket.send("%d %d" % (topic, messagedata))
    time.sleep(1)

subscriber.py

import sys
import zmq

port = "5556"

context = zmq.Context()
socket = context.socket(zmq.SUB)

print "Collecting updates from weather server..."
socket.connect ("tcp://127.0.0.1:%s" % port)


while True:
    print socket.recv()

I then execute them from terminal, and while publisher is publishing (i.e. printing outs the lines), subscriber never gets out of socket.recv()

Answer 1

adding

socket.setsockopt(zmq.SUBSCRIBE, "")

to subscriber, did the trick!

here is the updated subscriber.py

import sys
import zmq

port = "5556"

context = zmq.Context()
socket = context.socket(zmq.SUB)
socket.setsockopt(zmq.SUBSCRIBE, "")

print "Collecting updates from weather server..."
socket.connect ("tcp://127.0.0.1:%s" % port)

while True:
    print socket.recv()