Why was the indexed for loop removed in Kotlin?

Question

I still think "traditional" way of using the for loop is very powerful with full control of the index. Why was it removed in Kotlin?

what should I do in kotlin with following java code

for (int i = 0; i < n - 1; i++) {
   for (int j = i + 1; j < n; j++) {
   ....

Answer 1

The answer is: because they decided to remove it. You can still use this syntax:

for (a in 1..10) print("$a ")              // >>> 1 2 3 4 5 6 7 8 9 10

for (a in 10 downTo 1 step 2) print("$a ") // >>> 10 8 6 4 2 

For more info: Ranges & Loops

Answer 2

It was not "removed". The design of a new language doesn't start with the feature set of any existing language; we start with a language that has no features, and start adding features which are necessary to express certain behavior in a nice and idiomatic way. Up until now, we aren't aware of any behavior for which a C-style 'for' loop would be the nicest and most idiomatic way to express it.

Answer 3

Another useful way of retaining those indexes white iterating something (an Iterable, that is), is to use the withIndex() method. For example:

for((i, element) in myIterable.withIndex()){
    //do something with your element and the now known index, i
}

This I noticed achieves the same as what suggested in this answer, but I think it is better if we use the already built-in method Iterables have for such situations instead of implementing them again. This we could say is also similar to the forEachIndexed{} lambda:

myIterable.forEachIndexed{i, element ->
    //do something here as well
}