i ve been creating classes every time i ll look into destruc

Question

i ve been creating classes every time i ll look into destructive declarations thanks

adam-mcneilly · Answer

You d still need to create a data class to be returned by the function but then you can easily destructure at the call site The docs linked have a good example of this

Hullaballoonatic · Answer

yeah this is awesome i learned about two kotlin features today and i m all giddy

Shawn · Answer

Or I mean `Pair` or `Triple` can do in a pinch

Hullaballoonatic · Answer

yeah i love pair

adam-mcneilly · Answer

You can also destructure a pair

adam-mcneilly · Answer

So if you want to use it as the return type on your function you can still use destructuring at the call site slightly smiling face

Hullaballoonatic · Answer

you mean like it first and it second

adam-mcneilly · Answer

``` fun foo Pair lt Int Int gt val x y = foo ```

Shawn · Answer

< potter> ^

Shawn · Answer

might be relevant to what you re asking for

Shawn · Answer

unless you want named accessors in which case you ll need an inline `object ` expression

potter · Answer

oh yeah I forgot about those still not a general solution 4+ returns but covers most of my use cases

adam-mcneilly · Answer

You can destructure a `List lt T gt ` up to 5 items Any more than that and you d need a data class I d also argue that any more than that means you might want to question if destructuring is the most readable solution you may say yes but worth questioning after a point

Hullaballoonatic · Answer

yeah

Hullaballoonatic · Answer

if someone is returning like 8 distinct values from a fn then it is doing way more than it should

potter · Answer

yeah makes sense

adam-mcneilly · Answer

Definitely And if not that then it means those 8 values are actually connected in some way which leads me to believe they re better off as a data class because they represent something larger than the individual values

adam-mcneilly · Answer

Knowing that you can destructure a list is really nice because I think a good example use case is coordinates This is my favorite example for showing off destructuring `val x y z = arrayOf 5 10 5 ` Or looping through a map by destructuring the entry class `for key value in map `

Hullaballoonatic · Answer

haha i am literally working with coordinates right now

adam-mcneilly · Answer

sunglasses nailed it

potter · Answer

for the list all of the returned values have to have the same type right otherwise type inference won t work

adam-mcneilly · Answer

For the list I believe that s true Whatever ` lt T gt ` is for you list that s what you have to destructure to

adam-mcneilly · Answer

As far as I m aware I would have to test that out

Hullaballoonatic · Answer

so if i m rolling through an array that stores x1y1x2y2x3y3 is there a nicer way to iterate through them than ``` val arr = arrayOf 0 0 1 3 4 2 for i in arr indices step 2 arr i ++ arr i+1 ++ ``` using destructuring

potter · Answer

could whatever generates them generate a `Pair lt x y gt ` instead

adam-mcneilly · Answer

There is something like that

adam-mcneilly · Answer

`windowed` I believe But let me back up why have an array of x1y1x2y2 and not a list of pairs

Shawn · Answer

or `chunked` depending on your use case

Hullaballoonatic · Answer

well yeah I could do `List lt Pair lt Int Int gt gt ` but I m doing breadth first search and wanna be really efficient with memory

Hullaballoonatic · Answer

so i m using a bytearray

adam-mcneilly · Answer

hmm

Hullaballoonatic · Answer

i ve never used chunked either

adam-mcneilly · Answer

`chunked` is nice

adam-mcneilly · Answer

if you have your coordinates in the byte array you mentioned you can use `chunked` to get the `List lt Pair gt ` and then search through that I guess the performance hit is that you go through the list twice one to prettify it one to handle the coordinates I would think hard to know your exact use case

adam-mcneilly · Answer

Hullaballoonatic · Answer

i have trouble with collections in kotlin generating alterations on a base set of coordinates required some funkiness like this ``` val children List lt ByteArray gt get val result = ArrayList lt ByteArray gt val original = positions toList toImmutableList original forEachIndexed i byte gt result += original set i byte + 1 b toByteArray result += original set i byte 1 b toByteArray return result ```

Hullaballoonatic · Answer

this is AI stuff or i m throttled by memory not cpu

adam-mcneilly · Answer

Hmm let me tinker for a sec

potter · Answer

doesn t kotlin have lazy operations like java8 streams that let you prettify and consume in one iteration

Hullaballoonatic · Answer

i don t care how long it takes for the operation to run stuck out tongue

potter · Answer

I forget what they re called

Hullaballoonatic · Answer

delegates

Hullaballoonatic · Answer

i ve only ever used them for observables

adam-mcneilly · Answer

Casey can you give me an example of an input array and what you d expect as the output and I can tinker to see if there s a more idiomatic way to pull it off

Hullaballoonatic · Answer

it s not a large program if you want me to just hand it all over for context

potter · Answer

no sequences <https kotlinlang org api latest jvm stdlib kotlin sequences index html>

Hullaballoonatic · Answer

it s not working correctly atm

Hullaballoonatic · Answer

though

adam-mcneilly · Answer

hmm

adam-mcneilly · Answer

one sec

adam-mcneilly · Answer

I think I see what this is trying to do

Hullaballoonatic · Answer

potter · Answer

```fun main args Array lt String gt listOf 1 1 2 2 3 3 asSequence chunked 2 Pair it 0 it 1 map println $ it first $ it second toList ```

potter · Answer

that prints this ```1 1 2 2 3 3```

potter · Answer

obviously replace the println with an actual mapping

Hullaballoonatic · Answer

alright slick

potter · Answer

but only one `Pair` reference is held at a time so it doesn t require a lot of memory it ll create garbage though

adam-mcneilly · Answer

yeah I think that s what you re looking for

Hullaballoonatic · Answer

i also like to write `Pair it 0 it 1 ` as `it 0 to it 1 `

potter · Answer

oh yeah good call