How to find unique value from Array of object in Swift3 iOS

Question

I have declared an Array like :

  var sessionsToDisplayTemp : [SessionData] = []

The value of sessionsToDisplayTemp is:

[<SessionData: 0x600001c16a30> (entity: SessionData; id: 0x8b2a8ba144e57f29 <x-coredata://0A752C13-D33E-4AE2-BE3E-7B856C0EE8D9/SessionData/p3> ; data: {

    startTime = "14:30";
    switchInGroup = FALSE;

}), <SessionData: 0x600001c16a80> (entity: SessionData; id: 0x8b2a8ba144f97f29 <x-coredata://0A752C13-D33E-4AE2-BE3E-7B856C0EE8D9/SessionData/p4> ; data: {

    startTime = "13:30";
    switchInGroup = TRUE;

}), <SessionData: 0x600001c16cb0> (entity: SessionData; id: 0x8b2a8ba144fd7f29 <x-coredata://0A752C13-D33E-4AE2-BE3E-7B856C0EE8D9/SessionData/p5> ; data: {
        startTime = "13:30";
    switchInGroup = FALSE;

})]

My problem is I have to check the Start time, if the start time will be same then have to hide from this array and this array should be in the order of Start Time. I mean the final array should be :

[<SessionData: 0x600001c16a30> (entity: SessionData; id: 0x8b2a8ba144e57f29 <x-coredata://0A752C13-D33E-4AE2-BE3E-7B856C0EE8D9/SessionData/p3> ; data: {

        startTime = "13:30";
        switchInGroup = TRUE;

    }), <SessionData: 0x600001c16a80> (entity: SessionData; id: 0x8b2a8ba144f97f29 <x-coredata://0A752C13-D33E-4AE2-BE3E-7B856C0EE8D9/SessionData/p4> ; data: {

        startTime = "14:30";
        switchInGroup = FALSE;

    })]

I have done the ascending part based on Start time using :

sessionsToDisplayTemp.sort(by: { $0.startTime?.compare(($1.startTime)!) == .orderedAscending })

Can anyone help me to achieve this. Thank you.

sessionsToDisplayTemp.sort(by: { $0.startTime?.compare(($1.startTime)!) == .orderedAscending }) — Anand Gautam, Feb 16 '19 at 13:01
you can use `set` for your concept , see this for e.g : https://stackoverflow.com/questions/43790228/remove-duplicates-from-array-of-dictionaries-swift-3 — Anbu.Karthik, Feb 16 '19 at 13:04
Still same issue @Anbu.Karthik, Can you help me. The problem is I can set the order Start Time wise, but duplicate Start time value is not removing, — Anand Gautam, Feb 16 '19 at 13:14
try this also : https://stackoverflow.com/questions/41381075/swift-3-0-remove-duplicates-in-array-of-dictionaries?rq=1 — Anbu.Karthik, Feb 16 '19 at 13:14
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/188518/discussion-between-anand-gautam-and-anbu-karthik). — Anand Gautam, Feb 16 '19 at 13:16

score 0 · Accepted Answer · answered Feb 16 '19 at 14:18

0

This will create an array, out, that is sorted and without duplicates

var out = [SessionData]()
for data in sessionsToDisplayTemp.sorted(by: { $0.startTime < $1.startTime}) {
    if out.isEmpty {
        out.append(data)
    } else if let last = out.last, last.startTime != data.startTime {
        out.append(data)
    }
}

answered Feb 16 '19 at 14:18

Joakim Danielson

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Hi @Joakim, Thank you for your response, I am getting error: Binary operator '<' cannot be applied to two 'String?' operands. My startTime is String here.. – Anand Gautam Feb 16 '19 at 14:23
I am using : @NSManaged public var startTime: String? – Anand Gautam Feb 16 '19 at 14:25
@AnandGautam then I need to change the sorting part but why is startTime optional? – Joakim Danielson Feb 16 '19 at 14:28
sessionsToDisplayTemp.sort(by: { $0.startTime?.compare(($1.startTime)!) == .orderedAscending }) var out = [SessionData]() for data in sessionsToDisplayTemp{ if out.isEmpty { out.append(data) } else if let last = out.last, last.startTime != data.startTime { out.append(data) } } – Anand Gautam Feb 16 '19 at 14:32
Hi@Joakim, you there? I have a doubt here. – Anand Gautam Feb 16 '19 at 15:25
@AnandGautam what is your issue? – Joakim Danielson Feb 16 '19 at 15:31
The problem is I need to again sort the array based on switchInGroup Boolean. All true values should come first. Please guide me – Anand Gautam Feb 16 '19 at 15:33
sorted(by:) or sort(by:) takes a closure and in that closure you can define your own sorting algorithm there. See [this question](https://stackoverflow.com/questions/28781031/swift-sort-array-of-objects-based-on-boolean-value) – Joakim Danielson Feb 16 '19 at 15:39
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/188522/discussion-between-anand-gautam-and-joakim-danielson). – Anand Gautam Feb 16 '19 at 15:40
@AnandGautam I added a link – Joakim Danielson Feb 16 '19 at 15:45

Nikita Kurtin · Answer 2 · 2019-02-16T14:43:46.980

You can create a new array, where you would append only the SessionData objects with unique startTime. To make it easy, you can use Set as mentioned by @Anbu.Karthik in the comments.

As a simulation of your SessionDataI use a Tuple

var sessionToDisplay : [(startTime: String, switchInGroup: Bool)] = [
  (startTime: "14:30", switchInGroup: false),
  (startTime: "13:30", switchInGroup: true),
  (startTime: "13:30", switchInGroup: false),
];

Then the code would be like this:

var uniqueTimes = Set<String>();
var newArr : [(startTime: String, switchInGroup: Bool)] = [];

//Add only the objects with unique startTime (first occurrence in original array)
for (st, sig) in sessionToDisplay{
  if(uniqueTimes.insert(st).inserted){
    newArr.append((st, sig));
  }
}

//Sort as you need
newArr.sort(by: { $0.startTime.compare(($1.startTime)) == .orderedAscending });

How to find unique value from Array of object in Swift3 iOS

2 Answers2