快速修剪和映射数组中的第一个字母

Question

我有一个>2500个客户姓名的列表，并希望创建一个按字母顺序排列的lastNames索引(姓氏的第一个字母)。当LastName前面有空格时(我知道遗留数据问题，以后应该会修复)，它们应该被删除。如果没有可用的LastName，那么它应该作为indexArrayro中的最后一项出现。

结果应为大写的indexArray == "A“、"G”、"I“、"M”、"S“、"Z”、"“。

这就是我到目前为止所得到的。

struct MyObject {
    let firstName: String
    let lastName : String
}

let objectArray : [MyObject?] = [
    MyObject(firstName: "piet", lastName: "mozilla"),
    MyObject(firstName: "jol", lastName: " godzilla"),
    MyObject(firstName: "", lastName: "Anubis"),
    MyObject(firstName: "paul", lastName: ""),
    MyObject(firstName: "", lastName: "Strawberry"),
    nil,
    MyObject(firstName: "jol", lastName: "zwordfish"),
    MyObject(firstName: "jol", lastName: ""),
    MyObject(firstName: "", lastName: "Zwordfish"),
    nil,
    MyObject(firstName: "pot", lastName: "IronFly")
]


extension Array {  
    mutating func rearrange(from: Int, to: Int) {
        insert(remove(at: from), at: to)
    }
}

extension String
{   
    func trim() -> String
    {
        return self.trimmingCharacters(in: .whitespaces)
    }
}

let arrayWithNoNils = objectArray.flatMap { $0 } // to remove the 'nil's

let indexedArray = arrayWithNoNils.map({ $0.lastName.prefix(1) }) // get the first character

var indexArr : Array = Set(indexedArray).sorted() as Array // make it unique and sort

if indexArr.count > 0 && indexArr[0] == "" { // move the empty one as last
    let cnt = indexArr.count - 1
    indexArr.rearrange(from: 0, to: cnt)
}

在修剪方面有什么帮助吗？我想我可以把它用在

arrayWithNoNils.map({ $0.lastName.prefix(1) })

像这样的东西

arrayWithNoNils.map({ $0.lastName.trim.prefix(1) })

对此有什么建议吗？

一如既往的谢谢你。

Answer 1

这将通过使用compactMap删除nil对象并修剪和获取姓氏的第一个字符来为您提供索引数组。然后将其转换为一个集合以删除重复项，最后进行排序，其中闭包确保"“排在最后

let indexArray = Set(objectArray
    .compactMap { $0?.lastName.trimmingCharacters(in: .whitespaces).prefix(1).uppercased()})
    .sorted(by: {
        if $0.isEmpty {
            return false
        }
        if $1.isEmpty {
            return true
        }
        return $0 < $1
    })

Answer 2

您可以尝试以下操作：

let firstLetters = objectArray.map { item -> String in
    guard let item = item else { return "" }
    return String(item.lastName.trim().prefix(1)).uppercased()
}

let indexArray = Array(Dictionary(grouping: firstLetters, by: { $0 }).keys)
    .sorted {
        if $0 == "" { return false }
        if $1 == "" { return true }
        return $0 < $1
    }

print(indexArray) // ["A", "G", "I", "M", "S", "Z", ""]

Answer 3

这是你要找的吗？

let fixedArray = objectArray.map({ (object) -> MyObject? in
    guard let existedObject = object else { return nil }
    return MyObject(firstName: existedObject.firstName, lastName: existedObject.lastName.trimmingCharacters(in: .whitespacesAndNewlines))
})