Sort Array of Objects With Some Conditions - arrays

Question

I have an array of Users objects:
Class Users {
var firstName:String!
var lastName:String!
var status:Int!
override init(fn: String, ln: String, s: Int) {
self.firstName = fn
self.lastName = ln
self.status = s
}
}
var users:[Users] = [Users]()
users.append(Users(fn:"a", ln:"b", s:1))
users.append(Users(fn:"c", ln:"d", s:3))
users.append(Users(fn:"e", ln:"f", s:2))
users.append(Users(fn:"g", ln:"h", s:1))
users.append(Users(fn:"i", ln:"j", s:1))
users.append(Users(fn:"k", ln:"l", s:2))
I know the method to sort this array on status like
users = users.sorted(by: {$0.status > $1.status})
But, how could I sort users array on status with 2 on top then 3 and in the last 1 i.e [2,2,3,1,1,1]

Answer 1

Consider refactoring:
Class to struct:
struct User {
var firstName:String!
var lastName:String!
var status:Status
}
Status enum:
enum Status: Int {
case online, busy, offline
}
Population:
var users: [User] = [
User(firstName: "a", lastName: "b", status: .online),
User(firstName: "c", lastName: "d", status: .offline),
User(firstName: "e", lastName: "f", status: .busy),
User(firstName: "g", lastName: "h", status: .online),
User(firstName: "i", lastName: "j", status: .online),
User(firstName: "k", lastName: "l", status: .busy)
]
Sort:
users = users.sorted(by:{$0.status.rawValue < $1.status.rawValue })
users.forEach { print($0) }
Output:
User(firstName: a, lastName: b, status: .online)
User(firstName: g, lastName: h, status: .online)
User(firstName: i, lastName: j, status: .online)
User(firstName: e, lastName: f, status: .busy)
User(firstName: k, lastName: l, status: .busy)
User(firstName: c, lastName: d, status: .offline)

Answer 2

Try this. This will sort based on the order array. If any status is missing will be moved to bottom of the array.
let order = [2,3,1]
users = users.sorted(by: { order.index(of: $0.status) ?? Int.max < order.index(of: $1.status) ?? Int.max })
// 2,2,3,1,1,1
Lets say if 3 is missing in order array
let order = [2,1]
users = users.sorted(by: { order.index(of: $0.status) ?? Int.max < order.index(of: $1.status) ?? Int.max })
// 2,2,1,1,1,3

Answer 3

Use a lookup for your sort order.
let sortPriority: [Int: Int] = [ 1: 3, 2: 1, 3: 2]
Also you can use the mutating sort to sort the array in place instead of sorted which returns a copy since it looks like you are discarding the original array:
users.sort(by: {sortPriority [$0.status, default: Int.max] < sortPriority [$1.status, default: Int.max]})
print(users.flatMap{$0.status})
output:
[2, 2, 3, 1, 1, 1]