Arrays of Int arrays. Storing duplicates in order only

Question

I need to store an array of Int array for ordered duplicates (which are in a Array).

Example:

• Given array:
  mainArray = [7, 7, 3, 2, 2, 2, 1,

Answer 1

The following code will give you what you need...

let mainArray = [7, 7, 3, 2, 2, 2, 1, 7, 5, 5]
var newArray: [[Int]] = []

for var i=0; i < mainArray.count; i++ {
    let element = mainArray[i]
    if mainArray.indexOf(element) == i {
      var subArray = mainArray.filter({ $0 == element })
      newArray.append(subArray)
    }
}

print(newArray) // -> [[7, 7, 7], [3], [2, 2, 2], [1], [5, 5]]