Ruby count adjacent duplicate elements in array

Question

Given an array, say %w[ a b c a a b b c c c]. The method should return 3, as it is the maximum quantity of adjacent duplicates ( 3 'c' )

This is what I came up with so far:

def check_quantity_of_same_adjacent_elements(array)
  max = 0
  array.each_index do |i|
    max += 1 if array[i] == array[i+1]
  end
  max
end

but it obviously don't work as it returns the number of all duplicates

Why would you want to do this? Is this a homework question? (There's a homework tag if so) — ashes999
– ashes999, Commented Aug 28, 2014 at 14:42
No, it's not a homework, it's an actual task I have to accomplish in order to create slot machine in ruby — treeshateorcs
– treeshateorcs, Commented Aug 28, 2014 at 14:44

sawa · Accepted Answer · 2014-08-28 14:47:50Z

2

%w[a b c a a b b c c c].chunk{|e| e}.map{|_, v| v.length}.max #=> 3

answered Aug 28, 2014 at 14:47

sawa

169k51 gold badges287 silver badges398 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

treeshateorcs Over a year ago

Can you explain me what purpose does the underscore there serve? I only can find map.with_index which takes two parameters

the Tin Man Over a year ago

_ is known as a "black-hole" variable. It's used to assign values to, but never retrieve them, and is useful when you know something is going to be passed but want to ignore it.

Jörg W Mittag Over a year ago

This is just a community coding convention, but it has been so widely adopted that even the Ruby implementations were modified to nut generate an "unused parameter" or "unused local variable" warning for identifiers starting with an underscore.

Collectives™ on Stack Overflow

Ruby count adjacent duplicate elements in array

1 Answer 1

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related