Return the largest array from a set of arrays

Question

In Ruby what's the most elegant way to write a method that accepts a group of arrays as arguments and returns the array with the most number of elements?

def largest_array(*arrays)
end

For example, given:

a1 = [*0..9]
a2 = [*0..99]
a3 = [*0..49]
a4 = [*0..19]

largest_array(a1, a2, a3, a4) should return a2.

Note that the method must return a reference to the largest array itself, not the size. Also, in this case it doesn't matter which array is returned if there are arrays with identical sizes.

Answer 1

Using Enumerable#max_by:

def largest_array(*arrays)
  arrays.max_by &:size
end


a1 = [*0..9]
a2 = [*0..99]
a3 = [*0..49]
a4 = [*0..19]
largest_array(a1, a2, a3, a4) == a2  # => true