Let's combine the power of enumerables (#each, #map, etc.) and blocks (and yield). We'll want to create a splitter method which will take an array and divide it into two groups according to an arbitrary rule. You might want to split by age if we're talking about a group of people.
Implement a first method size_splitter which takes two parameters: an array, and a integer (the size). We will assume that the array only contains words, e.g. Strings, and that the arbitrary rule is to form two groups: the first one with words of the given size (second parameter of the method), and the other group with all the other words.
The size_splitter method should return an array of two arrays - the two groups defined above - with the contents sorted alphabetically.
words = %w(dog data ask my win two beer as)
result = size_splitter(words, 3)
# result => [["ask", "dog", "two", "win"], ["as", "beer", "data", "my"]]In the previous exercise, the abritrary rule was fixed. What if we wanted to let the method caller choose which rule to apply? We can do so with the power of blocks and yield!
Write a block_splitter method so that the following example works:
beatles = [ "John", "Paul", "Ringo", "George" ]
result = block_splitter(beatles) { |beatle| beatle.start_with?("P") }
# result => [ [ "Paul" ], [ "John", "Ringo", "George" ] ]