Find values in array of hashes to create new array of hashes

Question

I have some data returned from an api which I've parsed down to this:

[{:a=>value1, :b=>value2, :c=>value3, :d=>value4}, {:a=>value5, :b=>value6, :c=>value7, :d=>value8},{:a=>value9, :b=>value10, :c=>value11, :d=>value12}, ...]

How can I create a new array of hashes with the keys AND values of b and c, given key = b and key = c? I want to pass the key and return the value and maintain the key. So I want to end up with:

[{:b=>value2, :c=>value3}, {:b=>value6, :c=>value7}, {:b=>value10, :c=>value11}, ...]

Community · Accepted Answer · 2020-06-20 09:12:55Z

8

Pure ruby

array = [{:a=>'value1', :b=>'value2', :c=>'value3', :d=>'value4'}, {:a=>'value1', :b=>'value2', :c=>'value3', :d=>'value4'}]

b_and_c_array = array.map{|a| a.select{|k, _| [:b, :c].include?(k)} }

We take each hash using the map method that will return a result array. For each hash, we select only [:b, :c] keys. You can add more inside it.

Rails

If using Rails, let's use Hash#slice, prettier :

b_and_c_array = array.map{|a| a.slice(:b, :c) }

edited Jun 20, 2020 at 9:12

CommunityBot

11 silver badge

answered Nov 12, 2012 at 21:14

Anthony Alberto

10.4k3 gold badges36 silver badges39 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

alw615 Over a year ago

Wow! Worked like a charm. I'm trying to get lat and lng info from api data into json for google maps api rendering. This method lets me select the lat and lng values as [{lat=>value1, lng=>value2},...] but I need [{lat:value1, lng:value2}]. Any idea about this? Appreciate it.

Anthony Alberto Over a year ago

What do you mean? The api sends you malformed json back?

alw615 Over a year ago

I got it. Just needed to convert results to_json. Thanks!

Collectives™ on Stack Overflow

Find values in array of hashes to create new array of hashes

1 Answer 1

Pure ruby

Rails

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Pure ruby

Rails

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related