数组值应该像（字母，数字和特殊字符）
我试图按如下方式sorting：
let students: Set = ["23412334","&234@fwv","Kofi", "Abena", "Peter", "Kweku", "Akosua"] let sortedStudents = students.sorted() print(sortedStudents) 输出：
["&234@fwv", "23412334", "Abena", "Akosua", "Kofi", "Kweku", "Peter"]
但是我需要
["Abena", "Akosua", "Kofi", "Kweku", "Peter", "23412334","&234@fwv"]
let words = ["23412334","&234@fwv","Kofi", "Abena", "Peter", "Kweku", "Akosua"] func sortedNumbersLast(words: [String]) -> [String] { var startsWithDigit = [String]() var startsWithCharacter = [String]() var startsWithSymbol = [String]() for word in words { if let first = word.characters.first { if first >= "0" && first <= "9" { startsWithDigit.append(word) } else { if(!(first >= "a" && first <= "z") && !(first >= "A" && first <= "Z") ){ startsWithSymbol.append(word) }else{ startsWithCharacter.append(word) } } } } return startsWithCharacter.sorted(by: <) + startsWithDigit.sorted(by: <) + startsWithSymbol.sorted() } print(sortedNumbersLast(words: words))
["Abena", "Akosua", "Kofi", "Kweku", "Peter", "23412334", "&234@fwv"]
修改答案
做到这一点的“正确”方法是定义你自己的sorting比较器，并使用你的比较器sorted(by:)sorting。 在下面的例子中，我根据string中第一个字符的类别定义了一个“优先级”，然后是基于优先级的两级sorting，然后是正常stringsorting
extension String { enum Priority { case normal case low case lowest static let lowPriority: Set<Character> = Set(["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "0"]) static let lowestPriority: Set<Character> = Set(["&"]) static func < (a: Priority, b: Priority) -> Bool { switch (a, b) { case (.normal, .low), (.normal, .lowest), (.low, .lowest): return true default: return false } } } var priority: Priority { let first = self.characters.first! // fatal error for empty strings if Priority.lowestPriority.contains(first) { return .lowest } else if Priority.lowPriority.contains(first) { return .low } return .normal } } let students: Set = ["23412334","&234@fwv","Kofi", "Abena", "Peter", "Kweku", "Akosua"] let sortedStudents = students.sorted { (a, b) -> Bool in if a.priority < b.priority { return true } else if b.priority < a.priority { return false } return a < b } print(sortedStudents)
有可能还有错误，但它适用于你的testing用例。
按着这些次序
-
首先按照sorting的顺序对数组进行sorting。
-
删除以特殊字符开头的string并将其保存在另一个数组中。
- 删除以数字开头的string并将其保存在另一个数组中。
- 将数字数组附加到原始数组。
- 将特殊字符数组追加到原始数组中。