swift 在“filter”之后或通过查找“包含”的“firstIndex”从数组中删除项目

Question

我有两个 Books

数组

var tempArray = [Book]()
var filteredArray = [Book]()

其中

struct Book: Codable, Equatable {
    let category: String
    let title: String
    let author: String
}

如果 title 匹配，我想从 tempArray 中删除一本书。我可以像这样过滤 tempArray 搜索 "Some title"

filteredArray = tempArray.filter( { [=13=].title.range(of: "Some Title", options: .caseInsensitive) != nil } )

我正在尝试删除

if let i = tempArray.firstIndex(of: { [=14=].title.contains("Some Title") }) {
        tempArray.remove(at: i)
    }

但得到这个 Cannot invoke 'contains' with an argument list of type '(String)'。修复此错误的建议？或者，是否可以在过滤时删除元素？

Answer 1

你用错了方法。它应该是 func firstIndex(where predicate: (Self.Element) throws -> Bool) rethrows -> Self.Index? 而不是 func firstIndex(of element: Book) -> Int?

if let i = tempArray.firstIndex(where: { [=10=].title.contains("Some Title") }) {
    tempArray.remove(at: i)
}

另一种选择是使用RangeReplaceableCollection的方法mutating func removeAll(where shouldBeRemoved: (Book) throws -> Bool) rethrows:

tempArray.removeAll { [=11=].title.contains("Some Title") }

游乐场测试：

struct Book: Codable, Equatable {
    let category, title, author: String
}

var tempArray: [Book] = [.init(category: "", title: "Some Title", author: "")]
print(tempArray)   // "[__lldb_expr_12.Book(category: "", title: "Some Title", author: "")]\n"

tempArray.removeAll { [=13=].title.contains("Some Title") }
print(tempArray)  //  "[]\n"

swift 在“filter”之后或通过查找“包含”的“firstIndex”从数组中删除项目

swift remove item from array after `filter` or by finding `firstIndex that `contains`

arrays

filter

ios

swift

equatable