Question

我有一个对象集合，我想通过SortDate对对象进行排序，其中SortDate按最新日期到当前日期排序，然后从未来日期到过去日期排序。例如。如果我的Events数组包含SortDate等于6月4日，6月8日和6月20日的对象。我想对它进行排序，以便6月8日首先显示6月20日然后6月4日。其中6月8日最接近今天的日期6月6日我该怎么办？

这是我的尝试：

  self.eventsArray =  Array(self.realm.objects(Event.self).filter("EventType == \"Event\"").sorted(byKeyPath: "SortDate", ascending: false))
 let dateObjectsFiltered = self.eventsArray.filter ({ ($0.SortDate?.toDate)! > Date() })
  self.eventsArray = dateObjectsFiltered.sorted { return $0.SortDate! < $1.SortDate! }

Answer 1

您可以使用Array's sort(by:) function自定义数组排序。

以下是一个示例：

import Foundation

struct event {
    var SortDate: Date
}

//Create the array
var unsortedArray = [event]()
unsortedArray.append(event(SortDate: Date(timeIntervalSince1970: 1528070400)))
unsortedArray.append(event(SortDate: Date(timeIntervalSince1970: 1528416000)))
unsortedArray.append(event(SortDate: Date(timeIntervalSince1970: 1529452800)))


//Determine the closest date to the current date
let currentDate = Date(timeIntervalSinceNow: 0)
var lowestDiff = -1
var closestDate: Date?
var component:Set<Calendar.Component> = Set<Calendar.Component>()
component.insert(.second)

//Loop through the dates, keep track of the current closest date
for element in unsortedArray {
    let dateComponents = Calendar.current.dateComponents(component, from: currentDate, to: element.SortDate)

    if (lowestDiff == -1 || (abs(dateComponents.second!) < lowestDiff)) {
        lowestDiff = abs(dateComponents.second!)
        closestDate = element.SortDate
    }
}

//Sort the array
unsortedArray = unsortedArray.sorted(by:
    {
        //If the closest date is in the comparison, return the closest date as greater.
        if (closestDate != nil) {
            if ($0.SortDate == closestDate) {
                print($0.SortDate)
                return true
            }
            else if ($1.SortDate == closestDate){
                print($1.SortDate)
                return false
            }
        }

        //Otherwise, compare the dates normally
        return $0.SortDate > $1.SortDate
    }
)

Answer 2

你可以使用它，假设你所有的日期选项都不是零。

func days(fromDate: Date, toDate: Date) -> Int {
    return Calendar.current.dateComponents(Set<Calendar.Component>([.day]), from: fromDate, to: toDate).day ?? 0
}

let today = Date()

self.eventsArray.sort {
    let first = days(fromDate: today, toDate: $0.SortDate!.toDate!)
    let second = days(fromDate: today, toDate: $1.SortDate!.toDate!)
    return (first >= 0 && second < 0) ? true : ((first < 0 && second >= 0) ? false : (first < second))
}

如何将自定义排序应用于此对象数组？

2 个答案: