Sort array of objects by two properties

Question

This has been asked and answered before using NSSortDescriptor where it is quite easy. But is there a Swift-standard way using Array.sort()?

struct Sortable {     let isPriority: Bool     let ordering: Int } 

Sorting an array of Sortables by one property is simple:

sort { $0.ordering < $1.ordering } 

But I want to sort by isPriority then by ordering - and I can't get my head around a simple statement to make that happen.

Answer 1

Yes there is a very simple way using the Array.sort()

Code:

var sorted = array.sorted({ (s1, s2) -> Bool in     if s1.isPriority && !s2.isPriority {         return true //this will return true: s1 is priority, s2 is not     }     if !s1.isPriority && s2.isPriority {         return false //this will return false: s2 is priority, s1 is not     }     if s1.isPriority == s2.isPriority {         return s1.ordering < s2.ordering //if both save the same priority, then return depending on the ordering value     }     return false }) 

The sorted array:

true - 10 true - 10 true - 12 true - 12 true - 19 true - 29 false - 16 false - 17 false - 17 false - 17 false - 18 

Another a bit shorter solution:

let sorted = array.sorted { t1, t2 in     if t1.isPriority == t2.isPriority {       return t1.ordering < t2.ordering     }    return t1.isPriority && !t2.isPriority  } 

Answer 2

Here is a simple statement to do this sorting:

var sorted = array.sort { $0.isPriority == $1.isPriority ? $0.ordering < $1.ordering : $0.isPriority && !$1.isPriority }