Ruby on rails 如何使用';或';数组中的子句
我有一个数组,我想用Ruby on rails 如何使用';或';数组中的子句,ruby-on-rails,rails-activerecord,Ruby On Rails,Rails Activerecord,我有一个数组,我想用或子句调用作用域: cars = ['bmw', 'audi', 'toyota'] class Car < AR scope :from_bmw, -> { where(type: 'bmw') } scope :from_audi, -> { where(type: 'audi') } scope :from_toyota, -> { where(type: 'toyota') } end 我的cars数组可以更改;如果:cars=
或子句调用作用域:
cars = ['bmw', 'audi', 'toyota']
class Car < AR
scope :from_bmw, -> { where(type: 'bmw') }
scope :from_audi, -> { where(type: 'audi') }
scope :from_toyota, -> { where(type: 'toyota') }
end
我的cars
数组可以更改;如果:cars=['toyota'、'audi']
,我的方法应该产生:
Car.from_toyota.or(Car.from_audi)
我有如下几点:
def generate(cars)
scopes = cars.map {|f| "from_#{f} "}
scopes.each do |s|
# HOW TO I ITERATE OVER HERE AND CALL EACH SCOPE???
end
end
我不想将type作为参数传递给scope,这是有原因的。假设给定数组只包含有效的type
值,您可以简单地执行以下操作:
def generate(cars)
return Car.none if cars.blank?
scopes = cars.map {|f| "from_#{f} "}
scope = Car.send(scopes.shift)
scopes.each do |s|
scope = scope.or(Car.send(s))
end
scope
end
class Car
scope :by_type, -> (type) { where(type: type) }
end
types = ['bmw', 'audi', 'toyota']
Car.by_type(types) # => It'll generate a query using IN: SELECT * FROM cars WHERE type IN ('bmw', 'audi', 'toyota')
如果出于任何原因不想将数组作为参数传递给作用域,可以创建一个散列,将数组值映射到有效的by\u type
参数
VALID_CAR_TYPES = { volkswagen: ['vw', 'volkswagen'], bmw: ['bmw'], ... }
def sanitize_car_types(types)
types.map do |type|
VALID_CAR_TYPES.find { |k, v| v.include?(type) }.first
end.compact
end
Car.by_type(sanitize_car_types(types))
假设给定数组只包含有效的类型
值,您只需执行以下操作:
class Car
scope :by_type, -> (type) { where(type: type) }
end
types = ['bmw', 'audi', 'toyota']
Car.by_type(types) # => It'll generate a query using IN: SELECT * FROM cars WHERE type IN ('bmw', 'audi', 'toyota')
如果出于任何原因不想将数组作为参数传递给作用域,可以创建一个散列,将数组值映射到有效的by\u type
参数
VALID_CAR_TYPES = { volkswagen: ['vw', 'volkswagen'], bmw: ['bmw'], ... }
def sanitize_car_types(types)
types.map do |type|
VALID_CAR_TYPES.find { |k, v| v.include?(type) }.first
end.compact
end
Car.by_type(sanitize_car_types(types))
勾选此项您可以做一个简单的汽车。where(type:cars)
勾选此项您可以做一个简单的汽车。where(type:cars)