Channels
#stdlib
- d
dimsuz
08/26/2016, 3:43 PMthanks will read on it - d
dean
08/27/2016, 12:20 PMlist1.map { it.id }.intersect(listOfIds) - d
drfriendless
09/06/2016, 4:46 AMIs there something in the stdlib to turn an immutable collection into a mutable one? Typically I create a new instance of a Java collection class from the Kotlin value, but that feels wrong. Did I miss something? - k
kirillrakhman
09/06/2016, 6:48 AMAren't there
extension functions?toMutableX - j
jw
09/06/2016, 3:07 PMthere's also the copy constructors built into nearly every collection - o
orangy
09/06/2016, 3:12 PMNo, there is no
yet, but there is a plan to include some. Also there istoMutableX
to create mutable list right away.mutableListOf👍 1 - i
ilya.gorbunov
09/07/2016, 9:33 AM@orangy to be clear, there are
andtoMutableList
in 1.0. And there is notoMutableSet
which is coming in 1.1toMutableMap - h
hinst
09/13/2016, 10:32 AMto read stdout output of a program is there something special in kotlin std lib or should I just rip off from Java? - v
voddan
09/13/2016, 11:05 AMuse the Java tools - k
kirillrakhman
09/15/2016, 9:00 AMany cool + efficient way to find the item after a given item in an
?Iterable - k
kirillrakhman
09/15/2016, 9:03 AMcurrent solution:Copy codefun <T> Iterable<T>.itemAfterOrNull(item : T) : T? { val iter = iterator() while (iter.hasNext()) { if (iter.next() == item) return if (iter.hasNext()) iter.next() else null } return null } - o
orangy
09/15/2016, 9:07 AMlooks good enough - o
orangy
09/15/2016, 9:08 AMof course you can use
but it’s copyinglist.dropWhile { !cond }.firstOrNull() - k
kirillrakhman
09/15/2016, 12:17 PMit turns out, my requirements were even more complicated, so I just ended up putting it in a method - i
ilya.gorbunov
09/15/2016, 1:48 PMAnother option is to use
and hold the state (whetherfirstOrNull { }
was met) in the closure.item - k
kirillrakhman
09/15/2016, 2:48 PMI was thinking about that but the state would need to be boxed - i
ilya.gorbunov
09/15/2016, 3:55 PM@kirillrakhman Do you mean
-wrappers? Vote for the issue https://youtrack.jetbrains.com/issue/KT-5248kotlin.jvm.internal.Ref - k
kirillrakhman
09/15/2016, 5:12 PMthanks, I have - v
voddan
09/16/2016, 6:32 PMIf somebody wanted advanced math/combinatoric functionality, here is the first step: https://github.com/Kotlin/KEEP/issues/49 - d
drfriendless
09/17/2016, 7:35 AM@User uploaded a file: Returning a non-null value of a nullable type and commented: I have a bug in my get method in Catalog here - it can never return null even if null is the correct answer. I guess I could do it correctly by iterating over the entries of the map, but that's exactly not what a map is about. Is there some other way to code this that allows null to be returned if it's a legitimate answer? - y
yole
09/17/2016, 7:46 AMif (i in map) return map[i]; throw RuntimeException("not found") - d
drfriendless
09/17/2016, 12:55 PMThat doesn't work though. The type of map[i] is still T? so I can't return that as a T. Humans can infer that i in map implies that map[i] is a T (even if it is null), but IntelliJ does not seem to be able to. - y
yole
09/17/2016, 1:13 PMyou can use a cast:map[i] as T - d
drfriendless
09/17/2016, 1:15 PMAh yes, that does the job, thank you! - v
voddan
09/19/2016, 8:54 AMKotlin has
andfind
with identical semantics : https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/first-or-null.html https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/find.htmlfirstOrNull - v
voddan
09/19/2016, 8:55 AMI presume it is recommended to use
since it is more explicit and more kotlin-ishfirstOrNull - v
voddan
09/19/2016, 8:56 AMCan we deprecate
then with a message telling devs to usefind
instead ?firstOrNull - v
voddan
09/19/2016, 8:56 AMThat will reduce the fragmentation in the usages - v
voddan
09/19/2016, 8:57 AMThe motivation isThere should be one-- and preferably only one --obvious way to do it. - y
yole
09/19/2016, 8:57 AMno, this fragmentation was intentionally introduced