yes kotlinlang #getting-started

09/28/2018, 2:47 PM

09/28/2018, 2:47 PM

what have you tried

09/28/2018, 2:48 PM

val result = list1.intersect(list2)

some lamnba too, but i'm not confortable with those again

09/28/2018, 2:48 PM

If you want all elements that are not common between the two lists, you could do

list1.union(list2) - list1.intersect(list2)

09/28/2018, 2:50 PM

I need to find the first term of the second list that match the first list

ur 'sugestion give me the element of list 2 that aren't in list1, right?

09/28/2018, 2:53 PM

why dont u try it out

09/28/2018, 2:53 PM

I've just try it

it give me number that aren't in the first list

I 'v tought that ther was a kotlin way with lanmbda to do this

i'll keep looking

09/28/2018, 3:01 PM

The code above gives all elements of

list1

which are not in

list2

, and all elements in

list2

which are not in

list1

09/28/2018, 3:09 PM

yes, I saw that but that 's not what I need ^^

09/28/2018, 3:31 PM

It sounds as if you do want a.intersect(b) except maybe only the first element of that result?

09/28/2018, 3:34 PM

yes I think u've got the idea 🙂

var result: Long = 0
    for (element in r1) {
        for (element2 in r2) {
            if (element2 == element)
                result=element2
            break
        }

    }
    return result

I've done this, it's working but but not pretty ^^

09/28/2018, 3:36 PM

well yea so you want

a.intersect(b)[0]

09/28/2018, 3:37 PM

a.intersect(b).first()

it's working too

09/28/2018, 3:39 PM

ah yea [0] probably doesn't even work depending on what types I guess; np

09/28/2018, 3:40 PM

nope [0] doesn't work but . first() is ^^

so much better than my horrible loops 😂

09/28/2018, 3:44 PM

Note that you'll get a NoSuchElementException if it's empty though, you might want to do

a.intersect(b).firstOrNull() ?: 0

(to match your loops) or whatever you want as default value (Oh and btw for multiline code in slack use triple `)

09/28/2018, 3:47 PM

ilya.gorbunov

09/30/2018, 12:10 AM

If you want just the first item that is in both a and b, it would be more efficient to use

a.first { it in b }

firstOrNull

10/01/2018, 7:20 AM

thx! lambda are so obvious when I read it, but I still need to practice them 😁