Swift - Sort array of objects with multiple criteria

Question

I have an array of Contact objects:

var contacts:[Contact] = [Contact]()

Contact class:

Class Contact:NSOBjec         


        

Answer 1

The one thing the lexicographical sorts cannot do as described by @Hamish is to handle different sorting directions, say sort by the first field descending, the next field ascending, etc.

I created a blog post on how to this in Swift 3 and keep the code simple and readable.

You can find it here:

http://master-method.com/index.php/2016/11/23/sort-a-sequence-i-e-arrays-of-objects-by-multiple-properties-in-swift-3/

You can also find a GitHub repository with the code here:

https://github.com/jallauca/SortByMultipleFieldsSwift.playground

The gist of it all, say, if you have list of locations, you will be able to do this:

struct Location {
    var city: String
    var county: String
    var state: String
}

var locations: [Location] {
    return [
        Location(city: "Dania Beach", county: "Broward", state: "Florida"),
        Location(city: "Fort Lauderdale", county: "Broward", state: "Florida"),
        Location(city: "Hallandale Beach", county: "Broward", state: "Florida"),
        Location(city: "Delray Beach", county: "Palm Beach", state: "Florida"),
        Location(city: "West Palm Beach", county: "Palm Beach", state: "Florida"),
        Location(city: "Savannah", county: "Chatham", state: "Georgia"),
        Location(city: "Richmond Hill", county: "Bryan", state: "Georgia"),
        Location(city: "St. Marys", county: "Camden", state: "Georgia"),
        Location(city: "Kingsland", county: "Camden", state: "Georgia"),
    ]
}

let sortedLocations =
    locations
        .sorted(by:
            ComparisonResult.flip <<< Location.stateCompare,
            Location.countyCompare,
            Location.cityCompare
        )