ruby use array tvalues to index nested hash of hash [duplicate]

Answer 1

And then there's:

keys.inject(hash, :fetch)

or for earlier Ruby versions:

keys.inject(hash) {|h, k| h[k]}

If you did want to use recursion, a more Rubyesque approach would be:

def get_value(obj, keys)
  keys.empty? ? obj : get_value(obj[keys[0]], keys[1..-1])
end

Answer 2

h = {1 => {2 => {3 => "three"}},'a' => { 'b' => { 'c' => "basd"}}}
a = ['a','b', 'c']
a.inject(h, :[]) # => "basd"

h = {1 => {2 => {3 => "three"}},'a' => { 'b' => { 'c' => "basd"}}}
a = [1, 2, 3]
a.inject(h, :[]) # => "three"

Answer 3

Ruby 2.3.0 introduced a new method called dig on both Hash and Array that solves this problem entirely.

It returns nil if an element is missing at any level of nesting.

h1 = {}
h2 = { a: {} }
h3 = { a: { b: {} } }
h4 = { a: { b: { c: 100 } } }

h1.dig(:a, :b, :c) # => nil
h2.dig(:a, :b, :c) # => nil
h3.dig(:a, :b, :c) # => nil
h4.dig(:a, :b, :c) # => 100

Answer 4

Simple recursion

def getValue(hash, keys, i = 0)
  if i + 1 < keys.length
    getValue(hash[keys[i]], keys, i + 1)
  else
    hash[keys[i]]
  end
end

getValue(h, [1,2,3]) => "three"
getValue(h, ['a','b','c']) => "basd"