Rails对集合进行分组并对某些字段求和

orders = [
  { id: 1, product: 'A', price: 10 },
  { id: 2, product: 'B', price: 20 },
  { id: 3, product: 'A', price: 30 },
  { id: 4, product: 'C', price: 40 },
  { id: 5, product: 'B', price: 50 }
]

grouped_orders = orders.group_by { |order| order[:product] }

{
  'A' => [
    { id: 1, product: 'A', price: 10 },
    { id: 3, product: 'A', price: 30 }
  ],
  'B' => [
    { id: 2, product: 'B', price: 20 },
    { id: 5, product: 'B', price: 50 }
  ],
  'C' => [
    { id: 4, product: 'C', price: 40 }
  ]
}

sum_by_product = grouped_orders.transform_values { |orders| orders.sum { |order| order[:price] } }

{
  'A' => 40,
  'B' => 70,
  'C' => 40
}