The syntax is for defining Hash key/value pairs, and the difference depends on the Ruby version. Supported in both Ruby 1.8 and Ruby 1.9 :foo => true Supported only in Ruby 1.9 foo: true If you’re developing in Ruby 1.9 you should probably use the syntax: foo: true as it appears to be the direction … Read more
=> separates the keys from the values in a hashmap literal. It is not overloadable and not specifically connected to symbols. A hashmap literal has the form {key1 => value1, key2 => value2, …}, but when used as the last parameter of a function, you can leave off the curly braces. So when you see … Read more
The author of that blog post is being overly dramatic and foolish, the => is still quite necessary. In particular: You must use the rocket for symbols that are not valid labels: :$set => x is valid but $set: x is not. In Ruby 2.2+ you can get around this problem with quotes: ‘$set’: x … Read more
Yes, there is a difference. These are legal: h = { :$in => array } h = { :’a.b’ => ‘c’ } h[:s] = 42 but these are not: h = { $in: array } h = { ‘a.b’: ‘c’ } # but this is okay in Ruby2.2+ h[s:] = 42 You can also use … Read more