Swift 2.0 Sorting Array of Objects by Property

Question

In Swift 2.0, how would you go about sorting an array of custom objects by a property? I know in Swift 1.2, this was done using sorted() and sort(). However, these methods no longer work in Xcode 7 beta 4. Thanks!

For example:

class MyObject: NSObject {
    var myDate : NSDate
}

...

let myObject1 : MyObject = MyObject() //same thing for myObject2, myObject3

var myArray : [MyObject] = [myObject1, myObject2, myObject3] 

//now, I want to sort myArray by the myDate property of MyObject.

Answer 1

In Swift 2:

• You can use sort method, using compare to compare the two dates:

  let sortedArray = myArray.sort { $0.myDate.compare($1.myDate) == .OrderedAscending }  // use `sorted` in Swift 1.2
  

• Or, if you want to sort the original array, you can sortInPlace:

  myArray.sortInPlace { $0.myDate.compare($1.myDate) == .OrderedAscending }  // use `sort` in Swift 1.2
  

---

In Swift 3:

• to return a sorted rendition of the array, use sorted, not sort

  let sortedArray = myArray.sorted { $0.myDate < $1.myDate }
  

• to sort in place, it's now just sort:

  myArray.sort { $0.myDate < $1.myDate }
  

And with Swift 3's Date type, you can use the < operator.

Answer 2

If you want to sort original array of custom objects. Here is another way to do so in Swift 2.1

var myCustomerArray = [Customer]()
myCustomerArray.sortInPlace {(customer1:Customer, customer2:Customer) -> Bool in
        customer1.id < customer2.id
    }

Where id is an Integer. You can use the same < operator for String as well.

You can learn more about its use by looking at an example here: Swift2: Nearby Customers

Answer 3

In swift 3.0

I have taken the assumption same as the example asked in the question.

i.e customObject is MyObject with variable myDate. The array of the MyObject is myArray.We can sort like this simply.

myArray.sort(by: { (one: MyObject, two: MyObject) -> Bool in
    one. myDate < two. myDate
})

Answer 4

sort is now sortInPlace (or something similar) with the same parameters as sort.