Why declare objects separated by commas?

Question

What is the purpose of this line?

id, now = id+1, time.ctime()

I've never seen this usage of commas in Python before and I'm not sure how to Google this.

import zmq
import time

# ZeroMQ Context
context = zmq.Context()

# Define the socket using the "Context"
sock = context.socket(zmq.PUSH)
sock.bind("tcp://127.0.0.1:5690")

id = 0

while True:
    time.sleep(1)
id, now = id+1, time.ctime()

# Message [id] - [message]
message = "{id} - {time}".format(id=id, time=now)

sock.send(message)

print "Sent: {msg}".format(msg=message)

This is creating and unpacking tuples. This seems a good tutorial: https://www.tutorialspoint.com/python/python_tuples.htm — quamrana, Nov 01 '17 at 20:11
@quamrana I don't think the purpose here is to create a tuple. It is just creating two variables in this script. — theBrainyGeek, Nov 01 '17 at 20:18
But I think, technically, a tuple is created and unpacked in order that two assignments are performed in one line. — quamrana, Nov 01 '17 at 20:20

score 1 · Answer 1 · answered Nov 01 '17 at 20:16

1

This is a single command to assign values to two variables. It will be same as

id = id+1
now = time.ctime()

answered Nov 01 '17 at 20:16

theBrainyGeek

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I mean, sure, but this doesn't really address the syntax at all. – Adam Smith Nov 01 '17 at 20:16

kar · Answer 2 · 2017-11-01T20:21:20.750

0

keyword to google is 'tuple' . Its a immutable comma seperated list of values

edited Nov 01 '17 at 20:21

answered Nov 01 '17 at 20:13

kar

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`('some', 'values')` is also a tuple, an immutable comma-separated list of values – Adam Smith Nov 01 '17 at 20:17
ok I helped him with the key word to google : "I've never seen this usage of commas in Python before and I'm not sure how to Google this" . I only answered part of his answer. I have edited my answer – kar Nov 01 '17 at 20:20

Why declare objects separated by commas?

2 Answers2