How can I compare strings to an array to determine highest index value?

Question

I have several strings that I need to compare with values in an array to determine which has the highest index number. For example, the data looks like this:

array = [2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K', 'A']

v1 = "4"
v2 = "A"
v3 = "8"

How would I write it so that it would compare each value and return the fact that v2 is the winner based on the index number for A being 12?

Answer 1

A short version:

array = [2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K', 'A']

target = [4, "A", 8]
target & array  #=> [4, "A", 8]
array  & target #=> [4, 8, "A"]

(array & target ).last #=> "A"

target = ["B", "C"]
(array & target ).last #=> nil

Answer 2

You could write:

array = [2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K', 'A']
a = array.map(&:to_s)
  #=> ["2", "3", "4", "5", "6", "7", "8", "9", "10", "J", "Q", "K", "A"]

target = ["4", "A", "8"]
(target & a).empty? ? nil : a[target.map { |s| a.index(s) }.compact.max]
  #=> "A"

target = ["B", "C"]
(target & a).empty? ? nil : a[target.map { |s| a.index(s) }.compact.max]
  #=> nil

I have assumed that array may not be sorted.

Answer 3

array = [2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K', 'A']

v1 = "4"
v2 = "A"
v3 = "8"

array.reverse.map(&:to_s).find { |e| [v1, v2, v3].include?(e) }
# => "A"

or

array.reverse.map(&:to_s).find(&[v1, v2, v3].method(:include?))
# => "A"