<@U5QK61PK7> There is firstOrNull if you want to get nullable value. Reason - you can use `first` an...

# getting-started

[gildor]

@jasonlow There is firstOrNull if you want to get nullable value. Reason - you can use first and get nonnull result

[jasonlow]

Thanks for the reply @gildor, but I don’t really understand what you meant by

you can use `first` and get nonnull result

[jasonlow]

Doesn’t that mean I am guaranteed a result? But using ‘first’ clearly throws an exception, meaning there’s still a chance my result will be a null.

[jasonlow]

The only use case I can think for ‘first’ is if my dataset is guaranteed to have some data that might match my predicate.

[gildor]

No, of course it doesn’t guarantee result, it’s just different approaches, sometimes you want to get item or throw exception otherwise, so result will be non-nullable (so you shouldn’t handle possible nullable values)

If null result is okay for you case, just use firstOrNull

[voddan]

or find

[jasonlow]

I see, thanks for the help @gildor!

[jasonlow]

@voddan, what is the difference between firstOrNull and find?

[menegatti]

find will iterate the whole list trying to find the element that matches the predicate

[menegatti]

firstOrNull won't, as it will return on the 1st element or null right away

[jasonlow]

@menegatti Forgive me if I’m just blind or dumb, but from the source code it seems that find is just wrapping around firstOrNull

/**
 * Returns the first element matching the given [predicate], or `null` if no such element was found.
 */
@kotlin.internal.InlineOnly
public inline fun <T> Iterable<T>.find(predicate: (T) -> Boolean): T? {
    return firstOrNull(predicate)
}

[menegatti]

oh yeah, we are talking about different firstOrNull

[menegatti]

one that takes the parameter, which is exactly what you found

[menegatti]

and one that doesn't, which returns the first element of the list

[menegatti]

https://github.com/JetBrains/kotlin/blob/1.1.2/libraries/stdlib/src/generated/_Collections.kt#L194

[menegatti]

so yes, if you're using firstOrNull with a certain predicate, then it is the exact same thing as find

[gildor]

same thing as firstOrNull

as first. first is just alias for firstOrNull

[menegatti]

I meant to say find, fixed now

[voddan]

There was an argument about naming because find is used in other langs, but firstOrNull is more explicit and "kotlin way"

[voddan]

do find is an alias to findOrNull (it is also shorter)

[voddan]

AFAIK this is the only place in stdlib where functions duplicate each other