extracting data from a hash of arrays in ruby

Question

I'm new to ruby and working on a large data project and I'v got a nooby question.

I'v got a hash containing data of sales which is sorted by stores id:

hash = Hash.new(Array.new))
Sale.all.each {|sale| hash[sale.store_id].push( JSON.parse(sale.data)['items']) }

Now, I want to run over each store_id and get every item.promo_code = 24 and say how many item are there for each store.id .

Here is the data structure of the array inside of each key:

hash => 1 : Array [[{DATA,DATA,DATA}{DATA,DATA,DATA}]]

How would this be done in ruby?

Thank you very much in advance

EDIT:

I decided to attack this problem from a different angle

Sale.all.each {|sale| arr[sale.store_id] +=1 if (JSON.parse(sale.data)['items'].each{|item| item['buy_promotion_code']} == 24)  }

doesn't get me anything i get arr[#] = 0 all the time help : (

Answer 1

result_hash = {}

hash.each do |key, array|
  result_hash[key] = array.find_all({|item| item.promo_code = 24}).length
end

Answer 2

result_hash = {}

hash.each do |key, array|
  result_hash[key] += 1 if array[0] == 24
  puts array
end

where array[0] should give the value of promo_code of each item in the array.

Answer 3

My friend helped me with this.

he showed me the count function which simplified all this mess

this is the line that worked for me :

Sale.all.each {|sale| arr[sale.store_id] +=  (JSON.parse(sale.data)['items'].count {|item|  item['buy_promotion_code'] == "-1"}) }