kotlinlang #announcements

Hi guys! I got some problem on Kotlin. I write a onClickListener setter in Kotlin and call it with anonymous object, how to convert it to lambda or method reference? Does anyone know how to solve it? Thanks!!

How_to_use_lambda_or_method_reference_.php

pablisco

07/20/2018, 3:12 AM

Is there a way to go from a

Grouping

to a

Sequence

pablisco

07/20/2018, 3:13 AM

Similar to doing

map.toList()

pablisco

07/20/2018, 3:22 AM

I guess could always do:

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grouping.aggregate { key, sequence, element, _ ->
  sequence?.let { it + (key to element) } ?: sequenceOf(key to element)
}

user

07/20/2018, 6:26 AM

A file was commented on

user

07/20/2018, 6:35 AM

A file was commented on

user

07/20/2018, 6:36 AM

A file was commented on

Graham Smith

07/20/2018, 9:42 AM

Hi 👋

👋 3

user

07/20/2018, 9:56 AM

A file was commented on

user

07/20/2018, 10:02 AM

A file was commented on

user

07/20/2018, 10:04 AM

A file was commented on

Prateek

07/20/2018, 11:58 AM

http://mocklets.com If you are looking for a tool to automate your api testing for mobile or web application, try out http://mocklets.com It allows you to create mock apis with custom endpoints and support multiple responses per api, which can be updated on-the-go, which is very handy for testing team to test various scenarios without bothering server team. It also have a basic mock server, http://flashmock.mocklets.com/ to create basic mocks.

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gaspard

07/20/2018, 1:00 PM

I started using Kotlin with Eclipse 2 years ago, and I switch in less than one month, because Kotlin is made by jetbrains, which also provides Idea. So if you use Idea Intellij, you will have all the tooling, and the code will be written really smoothly !

gaspard

07/20/2018, 1:00 PM

especially if you want to work on a legacy project, Idea allows you to convert automatically a file (or a chunck of copy-pasted code) from java to kotlin

kef

07/20/2018, 4:00 PM

Hi, so I have this map of categories

categories: Map<Int, Int>

with key being category id, and value being id of a parent. For any given category I want to find full path, till parent id = 0. My current solution is kinda ugly:

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var id: Int = categoryId
val path = mutableListOf<Int>()
do {
    path.add(id)
    id = categories[id]!!
} while (id != 0)

How can I write this better, without yield?

Richard Cumberland

07/20/2018, 4:09 PM

seems like a tree might be a better structure, assuming that also facilitates the other operations you perform on the data?

kef

07/20/2018, 4:29 PM

This is simplified example, and this map is mainly used to get category data by category id. Getting category path is not common, but this code hurts my eyes a little bit 🙂 Not enough though to create another structure.

tipsy

07/21/2018, 10:48 AM

is it possible to make optional lines in a multiline string?

Nikky

07/21/2018, 12:13 PM

you mean have code

if else

in a multiline string ? multiline strings are raw strings, interpolation does not work in there afaik

Nikky

07/21/2018, 12:15 PM

you have the option of using normal strings or list of strings and then jointoString("\n") or to do some kind of formatting on the raw string and replace tokens

kristofdho

07/21/2018, 12:35 PM

interpollation does work

Nikky

07/21/2018, 2:24 PM

i stand corrected.. @tipsy you can do something like this

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fun main(args: Array<String>) {
    val line = "aaaaaaaa"
    val b = true
    println(
    """
    ${if(b) line else ""}
    """
    )
}

tipsy

07/21/2018, 2:30 PM

oh, that simple huh

tipsy

07/21/2018, 2:30 PM

thanks

Nikky

07/21/2018, 4:13 PM

take care of not accidentally leaving more newlines than indended..

Shawn

07/21/2018, 9:28 PM

Is there an equivalent to

Optional.filter()

maybe defined as an extension to

Any?

that I’m missing? right now I have a lengthy
?.let { if (predicate(it)) it else null }
and I couldn’t help but wonder if there’s a more idiomatic approach? I’m thinking of `takeIf`/`takeUnless`, thanks google!

rubber duck 2

perryprog

07/22/2018, 12:26 AM

I have a string where I need to replace a regex with something that depends on a capture group, so I used

replace(input: CharSequence, transform: (MatchResult) -> CharSequence): String

. I’m now realizing though that this doesn’t have the same behavior as findAll. Is there something like findAll, that replaces all occurrences of a regex with the result of a closure? Apologizes if I worded that badly.

karelpeeters

07/22/2018, 12:28 AM

What's the difference in behaviour you're talking about?

perryprog

07/22/2018, 12:28 AM

… wait, sorry one sec

perryprog

07/22/2018, 12:31 AM

ahhh, I’m stupid. Never mind, it was a regex mistake.

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