how to find index of duplicates items in array

Question

I am having a with graph, i need to remove duplicates values from array and "0" as well and i want to adjust array according to that for example


extension Array where Element: Equatable {
    var unique: [Element] {
        var uniqueValues: [Element] = []
        forEach { item in
            if !uniqueValues.contains(item) {
                uniqueValues += [item]
            }
        }
        return uniqueValues
    }
}

let speed = [0, 10, 20, 20, 40, 50, 50 ,50, 80, 90, 100]
let time = ["9", "10", "11", "12", "13", "15", "16", "17", "18", "19", "20"]

speed.unique // Return Only Unique Values

Now i want my time array to be updated. Example Index : 0, 3 - is removed from speed i want to remove index 0, 3 from time as well

Use one array of struct where the struct has speed and time properties. Then you much more easily sort and filter the array of struct. When done you could create the two final arrays from the final array of struct. — rmaddy
– rmaddy, Commented May 10, 2019 at 3:36
i am using speed as struct and time as [String], but no luck :( — istorry
– istorry, Commented May 10, 2019 at 3:39
Please read my comment again. You want one struct with both values and a single array. — rmaddy
– rmaddy, Commented May 10, 2019 at 3:41

ielyamani · Accepted Answer · 2019-05-10 03:59:17Z

2

You can do it this way:

let speed = [  0,   10,   20,   20,   40,   50,   50,   50,   80,   90,  100]
let time =  ["9", "10", "11", "12", "13", "15", "16", "17", "18", "19", "20"]

var sp = [Int]()
var tm = [String]()

for (i, x) in speed.enumerated() {
    if !sp.contains(x) {
        sp.append(x)
        tm.append(time[i])
    }
}

print(sp) //[  0,   10,   20,   40,   50,   80,   90,  100]
print(tm) //["9", "10", "11", "13", "15", "18", "19", "20"]

Choosing an appropriate type for time is advisable.

It is recommended in object-oriented programming to have speed and time as properties of a struct:

struct Mover {
    let speed: Int
    let time : TimeInterval
}

For example given this array:

let movers = [Mover(speed:   0, time:  9),
              Mover(speed:  10, time: 10),
              Mover(speed:  20, time: 11),
              Mover(speed:  20, time: 12),
              Mover(speed:  40, time: 13),
              Mover(speed:  50, time: 15),
              Mover(speed:  50, time: 16),
              Mover(speed:  50, time: 17),
              Mover(speed:  80, time: 18),
              Mover(speed:  90, time: 19),
              Mover(speed: 100, time: 20)]

You could keep the elements with a unique speed this way:

var speeds = Set<Int>()

let moversUniqueSpeed = movers.filter { speeds.insert($0.speed).inserted }

edited May 10, 2019 at 3:59

answered May 10, 2019 at 3:46

ielyamani

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1 Comment

istorry Over a year ago

i am so dumb why didn't i thought about this, Thank you very much.

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