Task

Select certain elements from an Array into a new Array in a generic way.



To demonstrate, select all even numbers from an Array.

As an option, give a second solution which filters destructively,
by modifying the original Array rather than creating a new Array.




# Enumerable#select returns a new array.
ary = [1, 2, 3, 4, 5, 6]
even_ary = ary.select {|elem| elem.even?}
p even_ary # => [2, 4, 6]
 
# Enumerable#select also works with Range.
range = 1..6
even_ary = range.select {|elem| elem.even?}
p even_ary # => [2, 4, 6]