method
find_index
find_index(p1)
public
Compares each entry in enum with value or passes to block. Returns the index for the first for which the evaluated value is non-false. If no object matches, returns nil
If neither block nor argument is given, an enumerator is returned instead.
(1..10).find_index { |i| i % 5 == 0 and i % 7 == 0 } #=> nil (1..100).find_index { |i| i % 5 == 0 and i % 7 == 0 } #=> 34 (1..100).find_index(50) #=> 49