swift - 如何在swift中将 'Date'类型的值转换为 'String'

Question

我想在返回 boolean 值之后重叠日期。

func overLap(start1: String, end1: String, start2: String, end2: String) -> Bool {
    if start1 < end2 && start2 < end1 {
        return false
    }
    return true
}

let start1 = "2019/02/01"
let end1 = "2019/02/20"
let start2 = "2019/02/15"
let end2 = "2019/03/02"

let dateFormatter = DateFormatter()

dateFormatter.dateFormat = "yyyy/MM/dd"

let dateFromString1 = dateFormatter.date(from: start1)
let dateFromString2 = dateFormatter.date(from: end1)
let dateFromString3 = dateFormatter.date(from: start2)
let dateFromString4 = dateFormatter.date(from: end2)

let myString = formatter.String(from: )

let result: Bool = overLap(start1: dateFromString1, end1: dateFromString2, start2: dateFromString3, end2: dateFromString4)
print(result)

这是错误:无法转换“日期”类型的值？到预期的参数类型“字符串” 让结果:Bool = overLap(start1: dateFromString1, end1: dateFromString2, start2: dateFromString3, end2: dateFromString4)

Answer 1

这是典型的类型不匹配错误。您无法比较苹果 (Date) 和橙子 (String)。

您不需要创建 Date 实例。将字符串与 numeric 选项进行比较

func overLap(start1: String, end1: String, start2: String, end2: String) -> Bool {
    if start1.compare(end2, options: .numeric) == .orderedAscending
        && start2.compare(end1, options: .numeric) == .orderedAscending {
        return false
    }
    return true
}

let start1 = "2019/02/01"
let end1 = "2019/02/20"
let start2 = "2019/02/15"
let end2 = "2019/03/02"

let result = overLap(start1: start1, end1: end1, start2: start2, end2: end2)
print(result)