Limiting loop for array of objects in Rails

While fetching records from DB, we can definitely limit the number of records to fetch as following.

@post.comments.limit(10).each do |comment|
   comment.description
end

But in practical, sometimes we face that we have an array of objects fetched from DB and we want to access first or last few objects. Using following code we can easily solve it. 

Reading first 10 records -

@posts.first(10).each do |post|
   post.title
end

Reading last 10 records -

@posts.last(10).each do |post|
   post.title
end