Good Morning guys, What is the best approach to fi...

# codereview

[Vivek Modi]

Good Morning guys, What is the best approach to find three items in single list. I tried some code and working fine. I want to know is there any better approach for this

val completeEvent = events?.lastOrNull { events -> events.status == "complete" }
val activeEvent = events?.find { events -> events.status == "active" }
val futureEvent = events?.firstOrNull { events -> events.status == "future" }

ApiResponse

"Events": [{
			"title": "Test 1",
			"status": "complete"
		}, {
			"title": "Test 2",
			"status": "complete"
		}, {
			"title": "Test 3",
			"status": "complete",
		}, {
			"title": "Test 4",
			"status": "complete"
		}, {
			"title": "Test 5",
			"status": "complete"
		}, {
			"title": "Test 6",
			"status": "active"
		}, {
			"title": "Test 7",
			"status": "future"
		}, {
			"title": "Test 8",
			"status": "future"
		}]

[Klitos Kyriacou]

I think it looks fine as it is (though I would use firstOrNull instead of find as its name shows the intent more clearly).

[Vivek Modi]

Hey @Klitos Kyriacou I tried some code, which one is more better.

val eventsGroup = events?.groupBy { it.status }
val completeEvent = eventsGroup?.get(COMPLETE_EVENT)?.lastOrNull()
val activeEvent = eventsGroup?.get(ACTIVE_EVENT)?.firstOrNull()
val futureEvent = eventsGroup?.get(FUTURE_EVENT)?.firstOrNull()

[Robert Williams]

Another option to clean things up is extension funs:

//Anywhere in the file outside the class
private fun Event.isComplete() = status == "complete"
...
val completeEvent = events?.lastOrNull(::isComplete)

[Klitos Kyriacou]

@Vivek Modi It depends. If you are planning to proceed and do something additional with eventsGroup, then using it at this point might be a good idea. But if you are only creating eventsGroup just for this purpose, then it doesn't look at all efficient.

Your original code will iterate backwards to find the last complete event, and then stop as soon as it finds it. It will iterate from the beginning to find the first active event and stop as soon as it finds it. The groupBy method will iterate the whole list regardless. It will also create potentially large lists which you don't need and throw away as you're only interested in 1 element.

[Vivek Modi]

Ok now I clearly understand that. Thank you so much @Klitos Kyriacou