Let's consider this as our hash c = {:test => {:foo => true}}
Normally, if we would like to print value of foo, we would access the hash like this c[:test][:foo] but I would like to access it dynamically based on my variable.
Therefore, let's consider the following variable path = [[:test],[:foo]].
How do I access the value true now? I have tried c[path] but it just says nil. What am I missing?
You can make use of dig. You can check the doc of dig here Hash#dig
c = { :test => { :foo => true } }
c[:test][:foo]
#=> true
c.dig(:test, :foo)
#=> true
path = [:test, :foo]
c.dig(*path)
#=> true
You just need to pass the hierarchy
Note: The
*beforepathinc.dig(*path)is reffered as splat operator
path is [[:test],[:foo]], not [:test, :foo].
flatten if the input value is [[:test],[:foo]]Old good recursive Ruby 1.9+ solution:
hash = {:test => {:foo => true}}
path = [[:test],[:foo]]
path.flatten.reduce(hash) { |h, p| h[p] }
#⇒ true
Or, as @Stefan suggested in comments:
path.reduce(hash) { |h, (p)| h[p] }
# or even
path.reduce(hash) { |h, p| h[p.first] }
More defensive:
path.flatten.reduce(hash) { |h, p| h.nil? ? nil : h[p] }
flatten via path.reduce(hash) { |h, (p)| h[p] }
pathvariable a nested array?