How do I find the first two consecutive elements in my array of numbers?

Question

Using Ruby 2.4, I have an array of unique, ordered numbers, for example

[1, 7, 8, 12, 14, 15]

How do I find the first two elements whose differ

Answer 1

You could use each_cons and find to get the first element from the array of pairs where the second element less the first one is equal to 1:

p [1, 7, 8, 12, 14, 15].each_cons(2).find { |a, b| b - a == 1 }
# => [7, 8]