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使用flatmap实现搜索功能

flatmap uisearchbar swift

128K · 技术社区 · 7 年前

var sections = [

        Section(sec: "One",
                subSec: ["A", "B", "C", "D", "E"],
                expanded: false),

        Section(sec: "Two",
                subSec: ["A", "B", "C", "D", "E"],
                expanded: false),

        Section(sec: "Three",
                subSec: ["A", "B", "C", "D", "E"],
                expanded: false),

struct Section {
    var sec: String!
    var subSec: [String]! // [ ] = Array of Strings
    var expanded: Bool!

    init(sec: String, subSec: [String], expanded: Bool) {
        self.sec = sec
        self.subSec = subSec
        self.expanded = expanded
    }
}

我正在尝试建立一个搜索功能。它适用于标准数组,但不适用于我的变量,因为它更复杂。我(在帮助下)使用flatmap调整了代码,但我不知道如何将其映射到子字符串。

func filterContentForSearchText(_ searchText: String, scope: String = "All") {
        filtered = sections.flatMap{ return $0.subSec.lowercased().contains(searchText.lowercased()) ? $0.subSec : nil }

        tableView.reloadData()
    }

我当前遇到的错误是: Value type [String] has no value lowercased

附加代码:

var filtered = [Section]()
let searchController = UISearchController(searchResultsController: nil)

3 回复 | 直到 7 年前

Adrian Bobrowski 7 年前

baseText.range(
    of: searchText, options: .caseInsensitive, range: nil, locale: nil
) != nil

如果你想得到整个部分,那么你不需要使用 flatMap filter

var filtered: [Section] = []

func filterContentForSearchText(_ searchText: String, scope: String = "All") {
    filtered = sections.filter { section in
        section.subSec.contains { 
            $0.range(
                of: searchText, options: .caseInsensitive, range: nil, locale: nil
            ) != nil 
        }
    }
}

但是,如果在该部分中,您只需要包含搜索文本的子部分,那么

var filtered: [Section] = []

func filterContentForSearchText(_ searchText: String, scope: String = "All") {
    filtered = sections.map { section in
        var section = section
        section.subSec = section.subSec.filter {
            $0.range(
                of: searchText, options: .caseInsensitive, range: nil, locale: nil
            ) != nil
        }
        return section
    }
}

var filtered: [String] = []

func filterContentForSearchText(_ searchText: String, scope: String = "All") {
    filtered = sections.flatMap { section in
        section.subSec.filter {
            $0.range(
                of: searchText, options: .caseInsensitive, range: nil, locale: nil
            ) != nil
        }
    }
}

Community THelper 4 年前

您的错误可以通过以下方式解决: map

[[String]] 而不是 [String]

sections 所以我得到一个1D数组,其中所有子部分都是字符串

要做第一件事,你需要 flatMap filter .

let filtered: [String] = 
    sections.flatMap { $0.subSec }
             .filter { $0.lowercased().contains(searchText.lowercased()) }

algrid 7 年前

$0.subSec.lowercased().contains(searchText.lowercased())

你可以试试

$0.subSec.contains({$0.lowercased() == searchText.lowercased()})