What is the Elixir equivalent to Ruby’s
Hash.new where you can specify a block that returns an empty list when you access a non-existent key (or Perl’s autovivification feature)?
The idea is that when you access a key in a Map that doesn’t exist you get back an empty list, which you can then append values to. And, if the key does exist, then you get back a non-empty list, which you can also append values to.
Also, why is it that the editor for this forum has a textbox that says “choose optional tags for this topic”, yet when I submit my question, I get an alert that says “You must choose at least 1 tag”, yet none of the tags are relevant to my question?