CODEWITHSUNDEEP
ruby
Jeremiah S.
Jeremiah S.

Reputation: 421

Select named array from a hash of array of arrays

I have a hash of an array of arrays. The array is indexed by the hash (that is the way I am reading this):

[
 {"name":"G18","data": [["X301",141],["x7901",57],["x2100",142],["x90",58]]},
 {"name":"G19","data": [["M16",141],["M203",57],["M29S",142]]},
 {"name":"G20","data": [["X301",141],["x7901",57],["x2100",142],["x90",58]]}
]

I want to select the hashes that contain the array G18, and return only the data.

I tried searching for answer, but I haven't found anything like this yet.

Upvotes: 1

Views: 97

Answers (3)

marmeladze
marmeladze

Reputation: 6564

This will work for you if you have only one item with name "G18":

a.find {|e| e[:name] == "G18" }[:data]

See: Enumerable#find in the official docs.

Upvotes: 3

Dylan Richards
Dylan Richards

Reputation: 786

collection = [
  {"name":"G18","data": [["X301",141],["x7901",57],["x2100",142],["x90",58]]},
  {"name":"G19","data": [["M16",141],["M203",57],["M29S",142]]},
  {"name":"G20","data": [["X301",141],["x7901",57],["x2100",142],["x90",58]]}
]

def data_for_name(name, collection)
  collection.find { |item| item[:name] == name }[:data]
end

p data_for_name("G18", collection)

Upvotes: 2

jvillian
jvillian

Reputation: 20263

Given:

ary = [
  {"name":"G18","data": [["X301",141],["x7901",57],["x2100",142],["x90",58]]},
  {"name":"G19","data": [["M16",141],["M203",57],["M29S",142]]},
  {"name":"G20","data": [["X301",141],["x7901",57],["x2100",142],["x90",58]]}
]

Try:

ary.select{|hsh| hsh[:name] == 'G18'}.first[:data]
 => [["X301", 141], ["x7901", 57], ["x2100", 142], ["x90", 58]]

In fact, marmeladze's answer is the correct one: 

ary.find{|hsh| hsh[:name] == 'G18'}[:data]

Using select was a misfire.

Upvotes: 3

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