Loop Within Loop in Rails Controller

Loop within Loop in Rails Controller

You are overwriting @posts with each iteration.
Try this:

def index
    @institution = Institution.find(current_user.institution.id)
    @categories = Category.all
    @posts = []
    @categories.each do |category|
      tposts = Post.where("category_id = ? and institution_id = ?", category, @institution).order("created_at DESC")
      @posts += tposts if tposts
    end
    authorize! :read, @post
    respond_with(@posts)
end

To retrieve all posts with non null category_id, try this:

def index
    @institution = Institution.find(current_user.institution.id)
    @categories = Category.all
    @posts = Post.where("category_id is not null and institution_id = ?", @institution).order("created_at DESC")
    authorize! :read, @post
    respond_with(@posts)
end

Change is not null to > 0 for integer category_id or != '' if your table contains '' instead of nulls.

Good luck.

Rails 4: How to put loop logic inside the controller

You can't render the view multiple times but you could do something like this.

def index
  @loops = [
    Item.where(featured: true).order("RANDOM()"),
    Item.order(:cached_votes_up => :desc),
    Item.order(:impressions_count => :desc),
    Item.order("created_at DESC")
  ]
end

And then in the template

- @loops.each do |loop|
 - loop.limit(4).each do |item|
   %li
     %h1 This is an example

Ruby Rails Loop in Controller

You do not seem to be populating your @cs_employees variable when you call @cs_employees.each

Also, there is way too much business logic in your controller. Move it to your model or a concern.

Instance Variable loop inside the controller

A better way to do this is to simply fetch the records from the db and store the whole collection in one instance variable.

@stores = Store.where(user_id: [1, 2, 3])

@markers = Gmaps4rails.build_markers(@stores) do |store, marker|
  marker.lat store.lat
  marker.lng store.long
  marker.title store.name
  marker.infowindow "#{store.store_infowindow}"
  # if they need different pictures handle it in the model
  marker.picture({
           :url => "//chart.apis.google.com/chart?chst=d_map_pin_letter&chld=TP|81DF08|000000",
           :width   => 52,
           :height  => 32
  })
end

Doing this:

  @rep1 = Store.where(:user_id => "1")
  @rep2 = Store.where(:user_id => "10")
  @rep3 = Store.where(:user_id => "11")
  @rep4 = Store.where(:user_id => "12")
  @rep5 = Store.where(:user_id => "13")
  @rep6 = Store.where(:user_id => "14")
  @rep7 = Store.where(:user_id => "15")

Is horrible for performance since each line will create a separate database query. If you are new at ruby I would suggest doing something like http://tryruby.org and learning how to manipulate arrays and hashes and the basics before trying to solve more complex problems.

Nested Each Loops Understanding

The below code should do

- @articles.each do |article|
  = article.text
  #level of indentation matters.
  - article.comments.each do |comment| #this will loop through respected article's comments
    = comment.text

How to loop through nested array in rails

I assume that SupplierItem object attributes should be taken from item_ids, location_ids and supplier_prices arrays by the same index.

The code:

@supplier = Supplier.new(supplier_params)
if @supplier.save
  item_params = params.require(:supplier_item).permit(item_ids: [], location_ids: [], supplier_prices: [])
  # => {"item_ids"=>["2", "4"], "location_ids"=>["1", "2"], "supplier_prices"=>["7.8", "45.0"]}
  items = item_params[:item_ids].zip(*item_params.values_at(:location_ids, :supplier_prices))
  # => [["2", "1", "7.8"], ["4", "2", "45.0"]]
  items.map do |item_id, location_id, supplier_price|
    supplier_item = SupplierItem.new({
      item_id:        item_id,
      location_id:    location_id,
      supplier_price: supplier_price,
      supplier_id:    @supplier.id,
    }.compact)
    supplier_item.save # TODO: check if it saved
  end
  flash[:success] = "New supplier created"
  redirect_to supplier_path(@supplier)
else
  render 'new'
end

PS: Don't use float/double for money.

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