CODEWITHSUNDEEP
iosarraysswiftsorting
Jessica
Jessica

Reputation: 9830

Sorting array gives me error

I have an array of structs. In the struct I have two NSDate objects: prop1 and prop2. I'm trying to sort prop1 from newest to oldest date/time. And I want prop2 to also get ordered based on prop1. (I will also want to do vice versa.)

struct Item {
    let prop1 : NSDate
    let prop2 : NSDate
}

var myItem = [Item]()

myItem.insert(Item(prop1: myDateSecond, prop2: anotherDateSecond), atIndex: 0)
myItem.insert(Item(prop1: myDateThird, prop2: anotherDateThird), atIndex: 0)
myItem.insert(Item(prop1: myDateFirst, prop2: anotherDateFirst), atIndex: 0)

myItem.sort { $0.prop1 < $1.prop1 }

At the last line of code, I get the following error:

Cannot invoke 'sort' with an argument list of type '((_, _) -> _)'

What am I doing wrong, and how can I fix it?

Upvotes: 2

Views: 61

Answers (1)

Leo Dabus
Leo Dabus

Reputation: 236260

When comparing two dates you have to use NSDate method compare:

struct Item {
    let prop1 : NSDate
    let prop2 : NSDate
}

var myItem = [Item]()

myItem.insert(Item(prop1: myDateSecond, prop2: anotherDateSecond), atIndex: 0)
myItem.insert(Item(prop1: myDateThird, prop2: anotherDateThird), atIndex: 0)
myItem.insert(Item(prop1: myDateFirst, prop2: anotherDateFirst), atIndex: 0)

myItem.sort{$0.prop1.compare($1.prop1) == NSComparisonResult.OrderedAscending}

Upvotes: 1

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