如何在swift中使用多个键的谓词搜索？答案

【问题标题】：How to use predicate search with multiple keys in swift?如何在swift中使用多个键的谓词搜索？
【发布时间】：2021-02-18 11:15:15
【问题描述】：

我想使用名字和姓氏应用搜索过滤器，并且我已经完成了单字段搜索，但我想同时应用名字和姓氏的搜索。

var cityData = [[String: Any]]()


cityData.append(["id":1,"city":"Chicago","last_name":"Swire","first_name":"Sharlene"])
cityData.append(["id":1,"city":"Allahabad","last_name":"Singh","first_name":"Abhay"])
cityData.append(["id":1,"city":"Delhi","last_name":"Jaiswal","first_name":"Shikhar"])



let predicate = NSPredicate(format: "SELF contains[c] %@", searchTerm)
let searchData = cityData.filter { predicate.evaluate(with: $0["first_name"] as? String ?? "") }

但上面的代码只过滤名字，但我也需要过滤姓氏

【问题讨论】：

对您收到的答案有任何反馈吗？

标签： ios swift predicate

【解决方案1】：

如果您想根据名字或姓氏查找城市，您可以像这样在过滤器操作中添加或条件 let searchData = cityData.filter { predicate.evaluate(with: $0["first_name"] as? String ?? "") || predicate.evaluate(with: $0["last_name"] as? String ?? "") }

请看下面的例子：

var cityData = [[String: Any]]()
    
    
    cityData.append(["id":1,"city":"Chicago","last_name":"Swire","first_name":"Sharlene"])
    cityData.append(["id":1,"city":"Allahabad","last_name":"Singh","first_name":"Abhay"])
    cityData.append(["id":1,"city":"Delhi","last_name":"Jaiswal","first_name":"Shikhar"])
    
    
    
    let predicate = NSPredicate(format: "SELF contains[c] %@", "l")
    let searchData = cityData.filter { predicate.evaluate(with: $0["first_name"] as? String ?? "") || predicate.evaluate(with: $0["last_name"] as? String ?? "") }
    print(searchData)

这将打印结果：

[["last_name": "Swire", "first_name": "Sharlene", "city": "Chicago", "id": 1], ["city": "Delhi", "last_name": "Jaiswal", "id": 1, "first_name": "Shikhar"]]

【讨论】：

【解决方案2】：

首先使用结构体而不是字典，这样可以避免所有丑陋的类型转换

struct CityData {
    let id : Int
    let city, firstName, lastName : String
}

var cityData = [CityData]()

cityData.append(CityData(id: 1, city: "Chicago", firstName: "Sharlene", lastName: "Swire"))
cityData.append(CityData(id: 2, city: "Allahabad", firstName: "Abhay", lastName: "Singh"))
cityData.append(CityData(id: 3, city: "Delhi", firstName: "Shikhar", lastName: "Jaiswal"))

不需要使用NSPredicate，Swift 对filter 数组和range(of:options:) 有一个有效的本地方法，带有caseInsensitive 选项的作用与NSPredicate 中的[c] 属性相同

let searchData = cityData.filter { $0.firstName.range(of: searchTerm, options: .caseInsensitive) != nil ||
                                   $0.lastName.range(of: searchTerm, options: .caseInsensitive) != nil
}

【讨论】：