Populate ruby Array1 with Array2 String element if and only if Array2 element matches Hash value(not key).

Question

I have a ruby hash:

VALS = { :one => "One", :two => "Two" }

and an Array:

array2 = ["hello", "world", "One"]

Question: How can I populate a new array1 so that it only pulls in any values in array2 that match exactly the values in VALS?

For example, I have tried: array2.each_with_index do |e,i| array1 << e if VALS[i] ~= e end

Along with other thing, and none work. Noob.

Thanks

Answer 1

Using nested loops would be very slow if both collections are large. It's better to treat the contents as sets:

array1 = VALS.values & array2
print array1

Output:

One

Answer 2

Here's an option:

hash = { :one => "One", :two => "Two" }
array = ["hello", "world", "One"]

p array.select { |i| hash.has_value? i }
# >> ["One"]

Answer 3

brilliant! but whent I tried:

p array.select { |i| hash.has_value? i ? array[i+1] : "foo"}

I got an can't convert fixnum error. I must be missing something.

Answer 4

got it!

array.select do |i|
  if VALS.has_value? i
    result << array[array.index(i)+1]
  end
end