concat

concat(*records)

Instance Public methods

Add one or more records to the collection by setting their foreign keys to the association's primary key. Since << flattens its argument list and inserts each record, push and concat behave identically. Returns self so method calls may be chained.

class Person < ActiveRecord::Base
  has_many :pets
end
 
person.pets.size # => 0
person.pets.concat(Pet.new(name: 'Fancy-Fancy'))
person.pets.concat(Pet.new(name: 'Spook'), Pet.new(name: 'Choo-Choo'))
person.pets.size # => 3
 
person.id # => 1
person.pets
# => [
#       #<Pet id: 1, name: "Fancy-Fancy", person_id: 1>,
#       #<Pet id: 2, name: "Spook", person_id: 1>,
#       #<Pet id: 3, name: "Choo-Choo", person_id: 1>
#    ]
 
person.pets.concat([Pet.new(name: 'Brain'), Pet.new(name: 'Benny')])
person.pets.size # => 5

Links:

https://github.com/rails/rails/blob/553e61af007553788813f81963a7621c82fff65d/activerecord/lib/active_record/associations/collection_proxy.rb#L332

doc_ruby_on_rails

2025-01-10 15:47:30

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