What are the benefits of the new hash syntax in Ruby 1.9?

Question

Apart from making it sightly more concise for defining hashes with symbols as keys, are there any other benefits of writing a hash as:

{key1: "value1", key2: "value2"} instead of {:key1 => "value1", :key2 => "value2"}?

Also, what is the convention when you have a mix of strings and symbols as hash keys?

Do you write it as {"key1" => "value1", key2: "value2"} or keep the style consistant as {"key1" => "value1", :key => "value2"}

possible duplicate of [Is it a bad style of using key: value instead of :key => value in a hash of Ruby 1.9](http://stackoverflow.com/questions/10631609/is-it-a-bad-style-of-using-key-value-instead-of-key-value-in-a-hash-of-ruby) — the Tin Man, Jul 10 '12 at 19:05
When using a mix of strings and symbols as keys, you should consider using [HashWithIndifferentAccess](http://api.rubyonrails.org/classes/ActiveSupport/HashWithIndifferentAccess.html) — Christoph Petschnig, Jul 12 '12 at 10:11

Dave Newton · Accepted Answer · 2012-07-10T14:34:02.927

12

It just looks nicer--it's syntactic sugar; it ends up being the same thing.

When mixing keys (ew, why would you do that?) I use the old hash-rocket syntax for the entire hash.

With symbol values I also use the old hash-rocket syntax for the entire hash–this looks icky:

{ ohai: :kthxbye }

I don't like mixing the two styles in the same hash–I think it's confusing.

This is all based on personal preference, though.

edited Jul 10 '12 at 14:34

answered Jul 10 '12 at 14:16

Dave Newton

1

So do you use the hash-rocket syntax only for the offending key/values or for the whole hash? – zsquare Jul 10 '12 at 14:21
Entire hash; I don't like mixing the two--I didn't make that clear; sorry. – Dave Newton Jul 10 '12 at 14:32

Matzi · Answer 2 · 2014-08-29T17:59:45.617

3

It's shorter, and similar to JavaScript notation. Not worth to migrate old notation to the new for any reason, but otherwise choose which you like.

Always keep the code consistent, don't mix notations. It's more readable that way.

edited Aug 29 '14 at 17:59

answered Jul 10 '12 at 14:17

Matzi

Actually it is similar to *JavaScript* notation, [*JSON*](http://json.org) requires the keys to be quoted as the keys are explicitly defined to be strings. – mu is too short Aug 29 '14 at 16:12

2 Answers2