Hi all, I was wondering is there a better way to c...

# getting-started

[antoniomarin]

Hi all, I was wondering is there a better way to create set or distinct lists from a list of objects based on their property? Currently I’m looping through each user and adding them one by one to the set

val userEmails = mutableSetOf<String>()
users.forEach {
    userEmails.add("Adding unique email: ${it.email}")
}
print(userEmails)

[serebit]

val userEmails = users.map { it.email }.toSet()

[antoniomarin]

I saw distinct as well, does anyone knows performance wise whats the difference between the two?

[antoniomarin]

Thanks all

[Shawn]

Actually, sorry, what I posted doesn’t exactly do what you’d want

[Shawn]

Campbell had it right the first time, more or less

[antoniomarin]

Yes but if I created regular list I could use distinct to add unique values 🙂

[Shawn]

performance-wise they’d be more or less identical, or at least they should on the JVM after a few runs

[Shawn]

I’d be surprised if HotSpot couldn’t figure out what you were doing here

[serebit]

So to summarize, the following work:
users.map { it.email }.toSet() // returns Set
users.map { it.email }.distinct() // returns List

[serebit]

thanks for making unnecessary changes to how markdown works, slack :)