Ruby Json access to nested element with key

Question

I'm trying to retrieve one value from a nested JSON with key.

My JSON structure is below:

If I try:

puts person_id["name"]

It does work fine, but then if I try to get the phone value as:

person_id.phone[0].["value"]

It doesn't work.

How can I properly access the phone value? Especially when primary field is true?

I tried this but no succcess. Thanks in advance.

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score 3 · Answer 1 · answered Jun 29 '16 at 18:42

From the looks of things, person_id is a hash with the string keys "name", "email", and "phone". The value with the key "phone" is an array, each element of which is a hash with the keys "label", "value", and "primary". In that case what you want is this:

phone_array = person_id["phone"]
# => [ { "label" => "Work", ... }, ... ]

first_phone = phone_array[0]
# => { "label" => "Work", ... }

first_phone_value = first_phone["value"]
# => "+0109135008"

Of course, you're looking for a way to do this in one line, which looks like this:

person_id["phone"][0]["value"]
# => "+0109135008"

Thanks Jordan. It really worked. And then I dont need to make any change to get the active phone since the current phone will be always on 0 level. Thanks again. — Julinho da Adelaide, Jun 29 '16 at 18:49

score 3 · Accepted Answer · answered Jun 29 '16 at 19:00

The only problem with your code was that you tried to use a dot-method accessor .phone when you should have used hash-key accessor ["phone"].

This is an understandable mistake. It'd work in Javascript.

It's actually not difficult to add this functionality. Ruby has the OpenStruct class which is a Hash-like object that automatically adds dot-method accessors. You'll just need to require ostruct, which is part of the standard lib.

You can tell JSON.parse to automatically convert all Hashes to OpenStructs (source):

object = JSON.parse(json, object_class: OpenStruct)

Or you can use the recursive-open-struct gem:

RecursiveOpenStruct.new(nested_hash)

Ruby Json access to nested element with key

2 Answers2