ruby find in array

1(1..10).detect   { |i| i % 5 == 0 and i % 7 == 0 }   #=> nil
2(1..10).find     { |i| i % 5 == 0 and i % 7 == 0 }   #=> nil
3(1..100).detect  { |i| i % 5 == 0 and i % 7 == 0 }   #=> 35
4(1..100).find    { |i| i % 5 == 0 and i % 7 == 0 }   #=> 35

1You can just use a set difference (aka minus) to see if one array includes all elements of another
2
3not_included = [1,2,3] - (1..9).to_a
4not_included      # => []
5
6not_included = [1,2,3,'A'] - (1..9).to_a
7not_included      # => ["A"]
8