Search object by id in custom type arraylist in kotlin [duplicate]

Question

It can be done easily in Java.

for(Event event:eventList){
if(event.id.equalTo(eventId){
  Event e=new Event();
   e=event;
}
}

I'm doing like this in Kotlin but expected result is not coming

  fun filterList(listCutom: List<Event>?) {
    listCutom!!.forEachIndexed { index, eventid ->
        if (listCutom[index].eventTypeId.equals(eventType)) {
            event= eventid
        }
    }
}

how can I do with Kotlin using filter or forEachIndexed or in another way efficiently?

Answer 1

You can use find extension function on the list:

val eventId = 3
val event: Event? = eventList.find { it.id == eventId }

Answer 2

Why do you use forEachIndexed in Kotlin code, since you don't need the index?
I don't know if the loop could find more than 1 objects and how you use e:

listCutom!!.forEach { event ->
    if (event.id.equalTo(eventId)) {
        val e = event
        //.................
    }
}

with filter:

val filtered = listCutom!!.filter { it.id.equalTo(eventId) }
filtered.forEach { ... }

If you want the indices of the list items that conform to a certain condition:

val indices = listCutom!!.mapIndexedNotNull { index, event ->  if (event.id.equalTo(eventId)) index else null}

then you can iterate through the indices list:

indices.forEach { println(it) }