extracting JSON name of a hash

The following segment of a JSON file needs to be transformed, essentially flattening it to a single hash for sizes

    "sizes" : {
      "small" : {
        "w" : "680",
        "h" : "261",
      },
      "large" : {
        "w" : "878",
         "h" : "337",
      },
      "medium" : {
        "w" : "878",
        "h" : "337",
      }

while the child attributes are accessible as:

 parent['sizes'].each do |size|
   w: size['w'],
   h: size['h'],
   label: size
 end

will not function, as the whole hash will be loaded for the label. How can the hash’s identity string only be captured?

>Solution :

For hashes each calls the block once for each key in hash, passing the key-value pair as parameters.

Like this:

parent['sizes'].each do |key, size|
  # format your preferred output here
  # key is small, large, medium
  # and size is {"w"=>"680", "h"=>"261"}, ...
  # for example
  {
    w: size['w'],
    h: size['h'],
    label: key
  }
end