如何对 swift 中的数组日期进行排序 4

Question

我有一组这样的日期:-

  var dateArray = ["2016-04-20", "2016-04-22", "2016-04-25", "2016-04-30"]

我想找出它们之间的天数差异。我做了一些研究，我只能用两个日期来做到这一点，这是我找到两个日期之间差异的方法

let dateFormatter = DateFormatter()
let isoDate = "2016-04-20"
let calendar = NSCalendar.current
let currentDate = Date()

在我的 viewDidLoad 方法中，我这样做了

    override func viewDidLoad() {
    super.viewDidLoad()



//  let components = calendar.dateComponents([.day], from: )
    dateFormatter.dateFormat = "yyyy-MM-dd"
    dateFormatter.locale = Locale(identifier: "en_US_POSIX") //en_US_POSIX
    let formatedStartDate = dateFormatter.date(from: isoDate)
    let date = dateArray.compactMap { dateFormatter.date(from: [=13=]) } // for date array
    print(date)
    let components = Set<Calendar.Component>([.day])
    let differenceOfDate = Calendar.current.dateComponents(components, from: formatedStartDate!, to: currentDate )

    print (differenceOfDate)
    apiData()
}

正如您在代码中看到的那样，我创建了一个常量 let isoDate = "2016-04-20" 并更改为 formatedStartDate并找到从这个日期到当前日期之间的差异，然后它就起作用了。但是，如果我有自己的日期数组怎么办？如何找到我自己的日期数组的差异并将其排序为升序或降序。请帮忙？

Answer 1

创建日期格式化程序

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
dateFormatter.locale = Locale(identifier: "en_US_POSIX") //en_US_POSIX

将日期字符串数组映射到 Date 个实例

let dateStringArray = ["2016-04-20", "2016-04-22", "2016-04-25", "2016-04-30"]
let dateArray = dateStringArray.map {dateFormatter.date(from: [=11=])!} // add .sorted() if the array is unordered.

在循环中获取相邻项之间的差异

var differences = [Int]()
for i in 0..<dateArray.count - 1 {
    let dayComponent = Calendar.current.dateComponents([.day], from: dateArray[i], to: dateArray[i+1])
    differences.append(dayComponent.day!)
}
print(differences)

Answer 2

我不确定您是只想比较相邻的日期还是比较每个日期。在第一种情况下，使用 vadians 解决方案。在另一种情况下，您可以这样做：

let dateStrings = ["2016-04-20", "2016-04-22", "2016-04-25", "2016-04-30"]

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
dateFormatter.locale = Locale(identifier: "en_US_POSIX")

let dates = dateStrings.compactMap { dateFormatter.date(from: [=10=]) }

let calendar = Calendar.current

var differences: [Int] = []
for i in 0..<dates.count {
    for j in i + 1..<dates.count {
        if let difference = calendar.dateComponents([.day], from: dates[i], to: dates[j]).day {
            differences.append(difference)
        }
    }
}

let descendingDifferences = differences.sorted(by: >)
print(descendingDifferences) // results in [10, 8, 5, 5, 3, 2]

如何对 swift 中的数组日期进行排序 4

How to sort an array dates in swift 4

nsdateformatter

ios

swift

swift4