How to Take index of List Item inside the For Loop in Android Kotlin?

Question

fun forLoopListItems() {
        val items = listOf("apple", "banana", "kiwifruit")
        for (i in items) {
            if (i.equals("banana")) {
              println("position is ${i.indices}")
            }
        }
    }

This is My Kotlin code used with For Loop. I tried to Print Index Curresponding to "banana" But Result is "System.out: position is 0..5" How is it Become 0..5 ?

Possible duplicate of [How to get the current index in for each Kotlin](https://stackoverflow.com/questions/48898102/how-to-get-the-current-index-in-for-each-kotlin) — Shahab Rauf, Apr 02 '18 at 09:11

s1m0nw1 · Answer 1 · 2018-04-02T11:09:28.410

4

The indices method gives you a range, which is 0..5 in this case because it's called on the String: banana with a length of 6.

You can instead iterate with indices as follows:

items.forEachIndexed { i, element ->
    if (element == "banana") {
        println("position is $i")
    }
}

Alternative ways of iterating with indices are listed in this post.

I'm not sure if you really want to iterate explicitly though. Maybe it's fine for you to use built-in functions for finding the index of your element:

println(items.indexOf("banana"))

edited Apr 02 '18 at 11:09

answered Apr 02 '18 at 09:15

s1m0nw1

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usage of -> is find in Many Places ,,why its Used? – Muhammed Haris Apr 02 '18 at 10:06

score 1 · Answer 2 · answered Apr 02 '18 at 09:18

There is indexOf:

Returns first index of element, or -1 if the collection does not contain element.

and lastIndexOf:

Returns last index of element, or -1 if the collection does not contain element.

val items = listOf("apple", "banana", "kiwifruit")
val appleIndex = items.indexOf("apple") // 0
val lastAppleIndex = items.lastIndexOf("apple") // 0
val bananaIndex = items.indexOf("banana")  // 1
val orangeIndex = items.indexOf("orange")  // -1

score 0 · Answer 3 · answered Aug 06 '20 at 13:13

You can iterate with Index using forEachIndexed method of Kotlin

Iterate with Index

itemList.forEachIndexed{index, item -> 
println("index = $index, item = $item ")
}

Check if item is Banana and print Index

itemList.forEachIndexed{ index, item -> {
         if (item.equals("banana")) {println("position is ${index}")}
              }

How to Take index of List Item inside the For Loop in Android Kotlin?

3 Answers3