Transform 2 d hash into 1 d hash

With this Hash:

{ "blog_namespace" : { "key" : "blog_post_1234",
                       "notice" : "Read the new blog post!开发者_C百科" } }

What's the quickest way to translate it into the Hash:

{ "blog_post_1234" : "Read the new blog post!" }

?

I always see people using clever combinations of map and merge etc, but can't quite get my head around a way to do this without nesting two loops together.

These hashes appear to be JSON objects. If they are, use a JSON parser to transform them into ruby hashes.

hash = {"blog_namespace" => {"key" => "blog_post_1234",
                             "notice" => "Read the new blog post!"}}

Hash[hash.map {|k, v| [v["key"], v["notice"]] }]
# => {"blog_post_1234" => "Read the new blog post!"}

This wasn't a valid Ruby hash. But given the assumptions that it is (or you'll parse it into one) and that the key will always be "blog_namespace", you can do the following:

>> Hash[[h["blog_namespace"].values]] 
#=> {"blog_post_1234"=>"Read the new blog post!"}