How would you make a comma-separated string from a list?

This my Answer to the stackoverflow question: How would you make a comma-separated string from a list?:

@jmanning2k using a list comprehension has the downside of creating a new temporary list. The better solution would be using itertools.imap which returns an iterator

from itertools import imap
l = [1, "foo", 4 ,"bar"]
",".join(imap(str, l))