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Group a Swift Model by date with auto sorting and asc/desc support (Swift 3) E.g.: for a UITableView with sections
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extension Sequence { | |
func groupSort(ascending: Bool = true, byDate dateKey: (Iterator.Element) -> Date) -> [[Iterator.Element]] { | |
var categories: [[Iterator.Element]] = [] | |
for element in self { | |
let key = dateKey(element) | |
guard let dayIndex = categories.index(where: { $0.contains(where: { Calendar.current.isDate(dateKey($0), inSameDayAs: key) }) }) else { | |
guard let nextIndex = categories.index(where: { $0.contains(where: { dateKey($0).compare(key) == (ascending ? .orderedDescending : .orderedAscending) }) }) else { | |
categories.append([element]) | |
continue | |
} | |
categories.insert([element], at: nextIndex) | |
continue | |
} | |
guard let nextIndex = categories[dayIndex].index(where: { dateKey($0).compare(key) == (ascending ? .orderedDescending : .orderedAscending) }) else { | |
categories[dayIndex].append(element) | |
continue | |
} | |
categories[dayIndex].insert(element, at: nextIndex) | |
} | |
return categories | |
} | |
} | |
/* | |
Usage: | |
class Model { | |
let date: Date! | |
let anotherProperty: String! | |
init(date: Date, _ anotherProperty: String) { | |
self.date = date | |
self.anotherProperty = anotherProperty | |
} | |
} | |
let modelArray = [ | |
Model(date: Date(), anotherProperty: "Original Date"), | |
Model(date: Date().addingTimeInterval(86400), anotherProperty: "+1 day"), | |
Model(date: Date().addingTimeInterval(172800), anotherProperty: "+2 days"), | |
Model(date: Date().addingTimeInterval(86401), anotherProperty: "+1 day & +1 second"), | |
Model(date: Date().addingTimeInterval(172801), anotherProperty: "+2 days & +1 second"), | |
Model(date: Date().addingTimeInterval(86400), anotherProperty: "+1 day"), | |
Model(date: Date().addingTimeInterval(172800), anotherProperty: "+2 days") | |
] | |
let groupSorted = modelArray.groupSort(byDate: { $0.date }) | |
print(groupSorted) // [["Original Date"], ["+1 day", "+1 day", "+1 day & +1 second"], ["+2 days", "+2 days", "+2 days & +1 second"]] | |
let groupSortedDesc = modelArray.groupSort(ascending: false, byDate: { $0.date }) | |
print(groupSortedDesc) // [["+2 days & +1 second", "+2 days", "+2 days"], ["+1 day & +1 second", "+1 day", "+1 day"], ["Original Date"]] | |
*/ |
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