Python join why is it string join list instead of list join string

Question

This has always confused me. It seems like this would be nicer:

my_list = ["Hello", "world"]
print my_list.join("-")
# Produce: "Hello-world"

Than this:

my_list = ["Hello", "world"]
print "-".join(my_list)
# Produce: "Hello-world"

Is there a specific reason it is like this?

Answer 1

950down voteaccepted

It's because any iterable can be joined, not just lists, but the result and the "joiner" are always strings.

E.G:

import urllib2
print '\n############\n'.join(
    urllib2.urlopen('http://data.stackexchange.com/users/7095'))