Question: i Have an array of strings with the following format,

`let sample_array = ["05:30","06:20","04:20","09:40"]`

When after we converted all `string` to `DATE` format ,How can we find the total time from this array.

Answer: 
For your case, I would suggest to handle it without looking at it as dates. You could get your desired result by implementing a function as:

```
func getTotalTime(_ array: [String]) -> String {
    // getting the summation of minutes and seconds
    var minutesSummation = 0
    var secondsSummation = 0

    array.forEach { string in
        minutesSummation += Int(string.components(separatedBy: ":").first ?? "0")!
        secondsSummation += Int(string.components(separatedBy: ":").last ?? "0")!
    }

    // converting seconds to minutes
    let minutesInSeconds = secondsToMinutes(seconds: secondsSummation).0
    let restOfSeconds = secondsToMinutes(seconds: secondsSummation).1

    return "\(minutesSummation + minutesInSeconds):\(restOfSeconds)"
}

// https://stackoverflow.com/questions/26794703/swift-integer-conversion-to-hours-minutes-seconds
func secondsToMinutes (seconds : Int) -> (Int, Int) {
    return ((seconds % 3600) / 60, (seconds % 3600) % 60)
}

```

Therefore:

```
let array = ["20:40" , "20:40"]
let result = getTotalTime(array)
print(result) // 41:20

```
From the question and comments it seems that you are trying to calculate the total time (in hours and minutes) from the given array.

```
let sample_array = ["05:30","06:20","04:20","09:40"]

func getTime(arr: [String]) -> Int {

  var total = 0
  for obj in arr {

      let comp = obj.split(separator: ":")

      var hours = 0
      var minutes = 0
      if let hr = comp.first, let h = Int(String(hr)) {
        hours = h * 60
      }

      if let mn = comp.last, let min = Int(String(mn)) {
        minutes = min
      }

      total += hours
      total += minutes

    }
    return total

}

let totalTime = getTime(arr: sample_array)
print(totalTime)

let hours = totalTime/60
let minutes = totalTime%60
print("\(hours) hours and \(minutes) minutes")

```

You can further calculates days, month and year also.

I hope it is what you want.