CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-3
patrick
patrick

Reputation: 9722

is this an improper use of MVC?

I have a layout with two <ul>'s that are floated and I wanted to have a some-what even number of items in each ul.

So, I wanted to break up my collection in half, and have one half in the first, and one in the other...

Originally I started thinking, ok I could have my view do:

<ul>
  @collection[0..(@collection.to_f / 2).ceil].each do
    <li> ... </li>
  end
</ul>

<ul>
  @collection[(@collection.to_f / 2).ceil..-1].each do
    <li> ... </li>
  end
</ul>

but that's pretty unattractive.. So then I started thinking about writing a helper to do that, but then I ended up just making scopes in my model:

scope :first_half, {:limit => (count.to_f / 2).ceil}
scope :last_half, {:offset => (count.to_f / 2).ceil}

<ul>
  Collection.first_half.each do
    <li> ... </li>
  end
</ul>

<ul>
  Collection.last_half..each do
    <li> ... </li>
  end
</ul>

but I felt like maybe that's not ideal since the view is the only thing referencing those scopes?

Upvotes: 1

Views: 75

Answers (3)

diedthreetimes
diedthreetimes

Reputation: 4115

I did this exact same thing about a month ago. I wrote an amazing extention to Enumerable to be able to split the collection into groups of N, and then realized ActiveSupport already provided exactly that (almost).

Take a look at in_groups(number, fill_with = nil) it will split an array into number groups, perfect for the view :)

Upvotes: 4

Karl
Karl

Reputation: 6165

I agree that you should be defining a view helper rather than a scope for your model. You could make the syntax nicer if you define view helpers rather than writing it inline.

# collection_helper.rb
def first_half(collection)
  collection[0..(collection.to_f / 2).ceil]
end

# index.html.erb
<ul>
  first_half(@collection).each do
    <li> ... </li>
  end
</ul>

Upvotes: 1

Jeff Paquette
Jeff Paquette

Reputation: 7127

Better to do something like:

Collection.each_slice(Collection.length / 2) { |half|
<ul>
    half.each do
    <li> ... </li>
    end
</ul>

}

Granted, if you have an odd number of entries in your collection, you will end up with 3 lists.

Upvotes: 1

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