CODEWITHSUNDEEP
ruby-on-railsruby
yellowreign
yellowreign

Reputation: 3638

Rails - Iterate thru Multiple Arrays

I'm looking for a more DRY way to iterate through some code. I have a User model and I want to keep count of certain Users in a ReportRecord model (for reporting).

I have a defined list of values of User.names that I want to record (i.e. "Jan", "Lisa", "Tina"). How can I make this code more DRY as the list is much longer than three values? 

@users = User.all
@users.each do |u|

  # this part repeats with different names
  quantity = u.where("name = ?", "Jan").count
  ReportRecord.create(:user_id => u.id, :name => "Jan", :quantity => quantity)

  # repeated code with different name
  quantity = u.where("name = ?", "Lisa").count
  ReportRecord.create(:user_id => u.id, :name => "Lisa", :quantity => quantity)

  # repeated code with different name
  quantity = u.where("name = ?", "Tina").count
  ReportRecord.create(:user_id => u.id, :name => "Tina", :quantity => quantity)

end

Upvotes: 0

Views: 91

Answers (2)

Ilya
Ilya

Reputation: 13487

I would sum all users first (1 query instead of 3):

quantity_by_name = User.select(:name).where(name: %w(Jan List Tina))
                       .group(:name).sum(:quantity)
#=> { 'Lisa' => 1, 'Jan' => 2, 'Tina' => 3 }
quantity_by_name.each do |name, quantity|
  ReportRecord.create(name: name, quantity: quantity)
end

Upvotes: 3

Arslan Ali
Arslan Ali

Reputation: 17812

names = %w(Jan List Tina)

names.each do |name|
  count = User.where(name: name).count
  ReportRecord.create(name: name, quantity: count) # I don't understand `u.id`
end

Upvotes: 2

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