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#getting-started
  • k

    karelpeeters

    11/08/2017, 12:48 PM
    list1.groupBy { it.length }
    ☝️ 1
  • t

    techie01

    11/08/2017, 12:49 PM
    by using fold
  • k

    karelpeeters

    11/08/2017, 12:49 PM
    Can you give an example of what you want to the result to be?
  • t

    techie01

    11/08/2017, 12:51 PM
    result = mapOf("3" to listOf("abc", "def"), "4" to listOf("abcd","pqrst"))
  • k

    karelpeeters

    11/08/2017, 12:52 PM
    Yup then mine should work.
  • t

    techie01

    11/08/2017, 12:52 PM
    i need to use fold in the code
    🤔 1
  • k

    karelpeeters

    11/08/2017, 12:52 PM
    Why?
  • t

    techie01

    11/08/2017, 12:54 PM
    to practise fold
  • k

    karelpeeters

    11/08/2017, 12:56 PM
    You could abuse fold like this: 
    list1.fold(mutableMapOf<Int, String>(), { map, it -> map.apply { put(it.size, it) })
  • k

    karelpeeters

    11/08/2017, 12:56 PM
    But please don't.
  • k

    karelpeeters

    11/08/2017, 1:18 PM
    Actually that doesn't work, you could fix it by creating lists and adding to them but this is just a bad idea.
  • g

    Gagan Kalra

    11/09/2017, 1:08 PM
    hi , I wanna start learn kotlin .
  • g

    Gagan Kalra

    11/09/2017, 1:08 PM
    where I can start from ?
  • m

    marstran

    11/09/2017, 1:09 PM
    Hi, I started out doing the koans here: http://try.kotlinlang.org/koans
  • k

    kristofdho

    11/09/2017, 1:10 PM
    and simply read a lot of documentation
  • t

    Thiago

    11/09/2017, 1:12 PM
    @Gagan Kalra EduTools plugin for Intellij IDEA or Android Studio is koans inside IDE
    ☝️ 1
  • g

    Gagan Kalra

    11/09/2017, 1:20 PM
    there is @Thiago , but i want to learn it from scratch , all I know is Java and now wanna try Kotlin out , but I'm not the documentation type
  • s

    stan0

    11/09/2017, 1:25 PM
    Isn’t “from scratch” reading the documentation? 🙂
  • k

    kristofdho

    11/09/2017, 1:39 PM
    the documentation is great though 😕
  • h

    Hubert

    11/09/2017, 3:01 PM
    hey @Gagan Kalra in such case I can recommend you read this book: https://www.manning.com/books/kotlin-in-action
    ➕ 2
    💯 2
  • j

    James

    11/09/2017, 3:15 PM
    Hi, complete newbie question - i've been reading about null safety and I can't find any examples of checking for null without creating a variable For example, i'd like to do
    Copy code
    kotlin
val obj = Object()
if (obj.property != null) {
    ...
}
  • j

    James

    11/09/2017, 3:15 PM
    Do i have to map 
    obj.property
    to a variable first? Or if not, what is the best practice here?
  • m

    menegatti

    11/09/2017, 3:16 PM
    it really depends
  • m

    menegatti

    11/09/2017, 3:16 PM
    what do you want to do with 
    property
    ?
  • j

    James

    11/09/2017, 3:16 PM
    Add it to an array (thanks for much for answering so quickly!)
  • m

    menegatti

    11/09/2017, 3:18 PM
    no worries… let’s say you have a bunch of these 
    Object
    with a nullable field that you want to add to an array
  • m

    menegatti

    11/09/2017, 3:18 PM
    you could, for instance, do 
    listOfObject.map { it.property }.filterNotNull()
    and have a list of the properties
  • m

    menegatti

    11/09/2017, 3:18 PM
    no null check needed
  • m

    menegatti

    11/09/2017, 3:20 PM
    however if you’re doing something like written bellow but 
    property
    is a 
    var
    , you might need to use the 
    !!
    Copy code
    if (obj.property != null) {
    propertyArray[propertyArray.size - 1] = obj.property!!
}
  • j

    James

    11/09/2017, 3:20 PM
    ah you beat me to it, that second one fits the use case better
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