Question

var str = "Hello, playground"
var dataArray : NSMutableArray = []
var sum = 0.00

func addNewIncomeRecord(_ id: String, date: String, description: String, amount: Double, currency: String, category: String, notes: String) {
    let dict = ["id" : id, "date" : date, "description" : description, "amount" : amount, "currency" : currency, "category" : category, "notes" : notes] as [AnyHashable : Any]

    dataArray.add(dict)
}

addNewIncomeRecord("1", date: "11-25", description: "Money", amount: 20.00, currency: "EUR", category: "Home", notes: "More Money")
addNewIncomeRecord("2", date: "11-25", description: "Rent", amount: 50.00, currency: "EUR", category: "Home", notes: "Rent Money")
addNewIncomeRecord("3", date: "11-25", description: "Hair", amount: 10.00, currency: "EUR", category: "Medical"  ,notes: "HairCut")

let homeValue = NSPredicate(format: "category == %@", "Home")
let filteredArray = (dataArray as NSMutableArray).filtered(using: homeValue)
print(filteredArray)

我过滤了所有＆＃34; Home＆＃34;类别。但是现在我想再次过滤filtersArray的金额。因此，只有两个（Home Arrays）的数量在一个额外的数组中。

Answer 1

不要在Swift中使用NSArray或NSMutableArray。使用Swift本机数组（和字典）。
一旦你这样做，就不需要NSPredicate。使用filter方法。
不要使用字典来保存您的数据。使用所需字段创建struct。

首先，在不创建struct的情况下，这是使用原生数组的简单解决方案：

var dataArray = [[String:Any]]()
var sum = 0.00

func addNewIncomeRecord(_ id: String, date: String, description: String, amount: Double, currency: String, category: String, notes: String) {
    let dict: [String:Any] = ["id" : id, "date" : date, "description" : description, "amount" : amount, "currency" : currency, "category" : category, "notes" : notes]

    dataArray.append(dict)
}

addNewIncomeRecord("1", date: "11-25", description: "Money", amount: 20.00, currency: "EUR", category: "Home", notes: "More Money")
addNewIncomeRecord("2", date: "11-25", description: "Rent", amount: 50.00, currency: "EUR", category: "Home", notes: "Rent Money")
addNewIncomeRecord("3", date: "11-25", description: "Hair", amount: 10.00, currency: "EUR", category: "Medical"  ,notes: "HairCut")

let filteredArray = dataArray.filter { $0["category"] as? String == "Home" }
let amounts = filteredArray.flatMap { $0["amount"] as? Double }
print(amounts)

以下是使用struct的解决方案。

struct Income {
    let id: String
    let date: String
    let description: String
    let amount: Double
    let currency: String
    let category: String
    let notes: String
}

var dataArray = [Income]()
var sum = 0.00

func addNewIncomeRecord(_ id: String, date: String, description: String, amount: Double, currency: String, category: String, notes: String) {
    let income = Income(id: id, date: date, description: description, amount: amount, currency: currency, category: category, notes: notes)

    dataArray.append(income)
}

addNewIncomeRecord("1", date: "11-25", description: "Money", amount: 20.00, currency: "EUR", category: "Home", notes: "More Money")
addNewIncomeRecord("2", date: "11-25", description: "Rent", amount: 50.00, currency: "EUR", category: "Home", notes: "Rent Money")
addNewIncomeRecord("3", date: "11-25", description: "Hair", amount: 10.00, currency: "EUR", category: "Medical"  ,notes: "HairCut")

let filteredArray = dataArray.filter { $0.category == "Home" }
let amounts = filteredArray.map { $0.amount }
print(amounts)

使用struct有许多优点。它对每个领域都是安全的。你可以使它Codable，这样可以更容易地保存和读取文件。

我过滤了一个字典的NSMutableArray，然后我想再次过滤一个Key

1 个答案: