ruby - array of substrings in array of strings

Question

I have two array of strings. Strings in one array might be the subset of string in other array. I need to find out which all strings in one array are the substrings of strings in the other array

Example:

arr1 = ["firestorm", "peanut", "earthworm"]
arr2 = ["fire", "tree", "worm", "rest"]

result:

res = ["fire","worm", "rest"]

My solution is mentioned below. But it takes a lot of time. I have to process Thousands of words.

Solution:

res =[]
arr1.each do |word1|
  arr2.each do |word2|
   if word1.include? word2
     res << word2
   end
  end
end

Please suggest me the faster way to to do this

Answer 1

Unfortunely we don't know your solution.

But Array takes up more memory space than String. So you can convert it.

arr1 = ["firestorm", "peanut", "earthworm"]
arr2 = ["fire", "tree", "worm", "rest"]

arr1 = arr1.join(',')

And then

res = arr2.select { |word| arr1.include?(word) } #=> ["fire", "worm", "rest"]

or

res = arr2.select { |word| arr1.match?(word) } #=> ["fire", "worm", "rest"]

or

res = arr2.select { |word| arr1.match(word) } #=> ["fire", "worm", "rest"]