Swift 如何将对象数组分解为数组数组？

Question

我有一组购买对象 [Purchase] 定义为：

struct Purchase {
    let count: Int
    let food: String
}

我如何才能将这个购买数组转换为具有相同计数 (Int) 的购买数组？

例如：

let input: [Purchase(count: 2, food: "popcorn"), Purchase(count: 3, food: "popcorn"),  Purchase(count: 2, food: "soda"),
            Purchase(count: 2, food: "popcorn"), Purchase(count: 2, food: "soda")]

output: [[Purchase]] = [[Purchase(count: 2, food: "popcorn"), Purchase(count: 2, food: "soda"),
          Purchase(count: 2, food: "popcorn"), Purchase(count: 2, food: "soda")], [Purchase(count: 3, food: "soda")]

Answer 1

答案在评论中，但看起来更干净一些。

Dictionary(grouping: input, by: \.count).map(\.value)

Swift 如何将对象数组分解为数组数组？

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