Lambda argument should be moved out of parentheses












1















IntelliJ gives the following complaint:




Lambda argument should be moved out of parentheses




val profile = loadProfiles()
profile.sortedWith(Comparator({ profile1, profile2 ->
if (profile1.age > profile2.age) return@Comparator 1
if (profile1.age < profile2.age) return@Comparator -1
return@Comparator 0
}))

data class Developer(var age: Int)

fun loadProfiles(): List<Developer> {
val listOfNumber = listOf<Developer>(Developer(2), Developer(5), Developer(3))

return listOfNumber
}


How should I format the above to get rid of the complaint? Also, the sorting code doesn't sort. What is causing the problem?










share|improve this question


















  • 1





    you may also be interested in profile.sortedBy { it.age } instead... Note also that it is not sorting the underlying list, but rather returning a new sorted list.

    – Roland
    Nov 19 '18 at 13:22













  • ... and I meant: Alt + Enter or click on the light bulb to let Intellij solve that issue for you...

    – Roland
    Nov 19 '18 at 13:25
















1















IntelliJ gives the following complaint:




Lambda argument should be moved out of parentheses




val profile = loadProfiles()
profile.sortedWith(Comparator({ profile1, profile2 ->
if (profile1.age > profile2.age) return@Comparator 1
if (profile1.age < profile2.age) return@Comparator -1
return@Comparator 0
}))

data class Developer(var age: Int)

fun loadProfiles(): List<Developer> {
val listOfNumber = listOf<Developer>(Developer(2), Developer(5), Developer(3))

return listOfNumber
}


How should I format the above to get rid of the complaint? Also, the sorting code doesn't sort. What is causing the problem?










share|improve this question


















  • 1





    you may also be interested in profile.sortedBy { it.age } instead... Note also that it is not sorting the underlying list, but rather returning a new sorted list.

    – Roland
    Nov 19 '18 at 13:22













  • ... and I meant: Alt + Enter or click on the light bulb to let Intellij solve that issue for you...

    – Roland
    Nov 19 '18 at 13:25














1












1








1








IntelliJ gives the following complaint:




Lambda argument should be moved out of parentheses




val profile = loadProfiles()
profile.sortedWith(Comparator({ profile1, profile2 ->
if (profile1.age > profile2.age) return@Comparator 1
if (profile1.age < profile2.age) return@Comparator -1
return@Comparator 0
}))

data class Developer(var age: Int)

fun loadProfiles(): List<Developer> {
val listOfNumber = listOf<Developer>(Developer(2), Developer(5), Developer(3))

return listOfNumber
}


How should I format the above to get rid of the complaint? Also, the sorting code doesn't sort. What is causing the problem?










share|improve this question














IntelliJ gives the following complaint:




Lambda argument should be moved out of parentheses




val profile = loadProfiles()
profile.sortedWith(Comparator({ profile1, profile2 ->
if (profile1.age > profile2.age) return@Comparator 1
if (profile1.age < profile2.age) return@Comparator -1
return@Comparator 0
}))

data class Developer(var age: Int)

fun loadProfiles(): List<Developer> {
val listOfNumber = listOf<Developer>(Developer(2), Developer(5), Developer(3))

return listOfNumber
}


How should I format the above to get rid of the complaint? Also, the sorting code doesn't sort. What is causing the problem?







kotlin






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 19 '18 at 13:06









AndroidDevAndroidDev

10.1k2393167




10.1k2393167








  • 1





    you may also be interested in profile.sortedBy { it.age } instead... Note also that it is not sorting the underlying list, but rather returning a new sorted list.

    – Roland
    Nov 19 '18 at 13:22













  • ... and I meant: Alt + Enter or click on the light bulb to let Intellij solve that issue for you...

    – Roland
    Nov 19 '18 at 13:25














  • 1





    you may also be interested in profile.sortedBy { it.age } instead... Note also that it is not sorting the underlying list, but rather returning a new sorted list.

    – Roland
    Nov 19 '18 at 13:22













  • ... and I meant: Alt + Enter or click on the light bulb to let Intellij solve that issue for you...

    – Roland
    Nov 19 '18 at 13:25








1




1





you may also be interested in profile.sortedBy { it.age } instead... Note also that it is not sorting the underlying list, but rather returning a new sorted list.

– Roland
Nov 19 '18 at 13:22







you may also be interested in profile.sortedBy { it.age } instead... Note also that it is not sorting the underlying list, but rather returning a new sorted list.

– Roland
Nov 19 '18 at 13:22















... and I meant: Alt + Enter or click on the light bulb to let Intellij solve that issue for you...

– Roland
Nov 19 '18 at 13:25





... and I meant: Alt + Enter or click on the light bulb to let Intellij solve that issue for you...

– Roland
Nov 19 '18 at 13:25












3 Answers
3






active

oldest

votes


















1















sortedWith(): Returns a list of all elements sorted according to the
specified [comparator]




So to sort profile list you have to assign the list returned by sortedWith() to profile (also change its declaration from val to var)



var profile = loadProfiles()
profile = profile.sortedWith(Comparator { profile1, profile2 ->
if (profile1.age > profile2.age) return@Comparator 1
if (profile1.age < profile2.age) return@Comparator -1
return@Comparator 0
})

profile.forEach { println(it.age) }


or



val profile = loadProfiles().sortedWith(Comparator { profile1, profile2 ->
if (profile1.age > profile2.age) return@Comparator 1
if (profile1.age < profile2.age) return@Comparator -1
return@Comparator 0
})


For the warning: press Alt+Enter and let InteliJ make the change.






share|improve this answer

































    3














    This warning is caused because in Kotlin labda parameters can (and actually should be) outside parentheses.



    See this:



    fun onClick(action: () -> Unit) { ... }


    When you use function like this you can use:



    view.onClick({ toast(it.toString())} )
    view.onClick() { toast(it.toString()) }
    view.onClick { toast(it.toString()) }


    All of those forms are correct (compiler will not fail), but in Kotlin Style Guide you'll find following statement:




    If a call takes a single lambda, it should be passed outside of
    parentheses whenever possible.




    @see https://kotlinlang.org/docs/reference/coding-conventions.html#lambda-formatting



    That's why IntellJ shows warning. You can click alt + enter and IntellJ should show correct solution, or just move lambda out of parentheses. And if labda is only argument remove parentheses also.
    When lambda have to be in parentheses? Only when it is not last parameter in function.






    share|improve this answer































      1














      As for your immediate problem, you just have to write it like this:



      profile.sortedWith(Comparator { profile1, profile2 ->
      if (profile1.age > profile2.age) return@Comparator 1
      if (profile1.age < profile2.age) return@Comparator -1
      return@Comparator 0
      }
      )


      However, the code still has several layers of unneeded verbosity. Here are some ways to make it both more concise and more readable.





      1. Remove the return statement:



        profile.sortedWith(Comparator { profile1, profile2 ->
        if (profile1.age > profile2.age) 1
        else if (profile1.age < profile2.age) -1
        else 0
        })



      2. Use when instead of an if-else cascade:



        profile.sortedWith(Comparator { profile1, profile2 ->
        when {
        profile1.age > profile2.age -> 1
        profile1.age < profile2.age -> -1
        else -> 0
        }
        })



      3. use Int.compareTo:



        profile.sortedWith(Comparator { profile1, profile2 ->
        profile1.age.compareTo(profile2.age)
        }



      4. use compareBy:



        profile.sortedWith(compareBy(Profile::age))



      5. Don't use the general sortedWith when all you need is sortedBy:



        profile.sortedBy(Profile::age)







      share|improve this answer
























      • or better (I think) .sortedBy { it.age }

        – forpas
        Nov 19 '18 at 15:06











      Your Answer






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      3 Answers
      3






      active

      oldest

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      3 Answers
      3






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      1















      sortedWith(): Returns a list of all elements sorted according to the
      specified [comparator]




      So to sort profile list you have to assign the list returned by sortedWith() to profile (also change its declaration from val to var)



      var profile = loadProfiles()
      profile = profile.sortedWith(Comparator { profile1, profile2 ->
      if (profile1.age > profile2.age) return@Comparator 1
      if (profile1.age < profile2.age) return@Comparator -1
      return@Comparator 0
      })

      profile.forEach { println(it.age) }


      or



      val profile = loadProfiles().sortedWith(Comparator { profile1, profile2 ->
      if (profile1.age > profile2.age) return@Comparator 1
      if (profile1.age < profile2.age) return@Comparator -1
      return@Comparator 0
      })


      For the warning: press Alt+Enter and let InteliJ make the change.






      share|improve this answer






























        1















        sortedWith(): Returns a list of all elements sorted according to the
        specified [comparator]




        So to sort profile list you have to assign the list returned by sortedWith() to profile (also change its declaration from val to var)



        var profile = loadProfiles()
        profile = profile.sortedWith(Comparator { profile1, profile2 ->
        if (profile1.age > profile2.age) return@Comparator 1
        if (profile1.age < profile2.age) return@Comparator -1
        return@Comparator 0
        })

        profile.forEach { println(it.age) }


        or



        val profile = loadProfiles().sortedWith(Comparator { profile1, profile2 ->
        if (profile1.age > profile2.age) return@Comparator 1
        if (profile1.age < profile2.age) return@Comparator -1
        return@Comparator 0
        })


        For the warning: press Alt+Enter and let InteliJ make the change.






        share|improve this answer




























          1












          1








          1








          sortedWith(): Returns a list of all elements sorted according to the
          specified [comparator]




          So to sort profile list you have to assign the list returned by sortedWith() to profile (also change its declaration from val to var)



          var profile = loadProfiles()
          profile = profile.sortedWith(Comparator { profile1, profile2 ->
          if (profile1.age > profile2.age) return@Comparator 1
          if (profile1.age < profile2.age) return@Comparator -1
          return@Comparator 0
          })

          profile.forEach { println(it.age) }


          or



          val profile = loadProfiles().sortedWith(Comparator { profile1, profile2 ->
          if (profile1.age > profile2.age) return@Comparator 1
          if (profile1.age < profile2.age) return@Comparator -1
          return@Comparator 0
          })


          For the warning: press Alt+Enter and let InteliJ make the change.






          share|improve this answer
















          sortedWith(): Returns a list of all elements sorted according to the
          specified [comparator]




          So to sort profile list you have to assign the list returned by sortedWith() to profile (also change its declaration from val to var)



          var profile = loadProfiles()
          profile = profile.sortedWith(Comparator { profile1, profile2 ->
          if (profile1.age > profile2.age) return@Comparator 1
          if (profile1.age < profile2.age) return@Comparator -1
          return@Comparator 0
          })

          profile.forEach { println(it.age) }


          or



          val profile = loadProfiles().sortedWith(Comparator { profile1, profile2 ->
          if (profile1.age > profile2.age) return@Comparator 1
          if (profile1.age < profile2.age) return@Comparator -1
          return@Comparator 0
          })


          For the warning: press Alt+Enter and let InteliJ make the change.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 19 '18 at 13:26

























          answered Nov 19 '18 at 13:20









          forpasforpas

          11.9k3424




          11.9k3424

























              3














              This warning is caused because in Kotlin labda parameters can (and actually should be) outside parentheses.



              See this:



              fun onClick(action: () -> Unit) { ... }


              When you use function like this you can use:



              view.onClick({ toast(it.toString())} )
              view.onClick() { toast(it.toString()) }
              view.onClick { toast(it.toString()) }


              All of those forms are correct (compiler will not fail), but in Kotlin Style Guide you'll find following statement:




              If a call takes a single lambda, it should be passed outside of
              parentheses whenever possible.




              @see https://kotlinlang.org/docs/reference/coding-conventions.html#lambda-formatting



              That's why IntellJ shows warning. You can click alt + enter and IntellJ should show correct solution, or just move lambda out of parentheses. And if labda is only argument remove parentheses also.
              When lambda have to be in parentheses? Only when it is not last parameter in function.






              share|improve this answer




























                3














                This warning is caused because in Kotlin labda parameters can (and actually should be) outside parentheses.



                See this:



                fun onClick(action: () -> Unit) { ... }


                When you use function like this you can use:



                view.onClick({ toast(it.toString())} )
                view.onClick() { toast(it.toString()) }
                view.onClick { toast(it.toString()) }


                All of those forms are correct (compiler will not fail), but in Kotlin Style Guide you'll find following statement:




                If a call takes a single lambda, it should be passed outside of
                parentheses whenever possible.




                @see https://kotlinlang.org/docs/reference/coding-conventions.html#lambda-formatting



                That's why IntellJ shows warning. You can click alt + enter and IntellJ should show correct solution, or just move lambda out of parentheses. And if labda is only argument remove parentheses also.
                When lambda have to be in parentheses? Only when it is not last parameter in function.






                share|improve this answer


























                  3












                  3








                  3







                  This warning is caused because in Kotlin labda parameters can (and actually should be) outside parentheses.



                  See this:



                  fun onClick(action: () -> Unit) { ... }


                  When you use function like this you can use:



                  view.onClick({ toast(it.toString())} )
                  view.onClick() { toast(it.toString()) }
                  view.onClick { toast(it.toString()) }


                  All of those forms are correct (compiler will not fail), but in Kotlin Style Guide you'll find following statement:




                  If a call takes a single lambda, it should be passed outside of
                  parentheses whenever possible.




                  @see https://kotlinlang.org/docs/reference/coding-conventions.html#lambda-formatting



                  That's why IntellJ shows warning. You can click alt + enter and IntellJ should show correct solution, or just move lambda out of parentheses. And if labda is only argument remove parentheses also.
                  When lambda have to be in parentheses? Only when it is not last parameter in function.






                  share|improve this answer













                  This warning is caused because in Kotlin labda parameters can (and actually should be) outside parentheses.



                  See this:



                  fun onClick(action: () -> Unit) { ... }


                  When you use function like this you can use:



                  view.onClick({ toast(it.toString())} )
                  view.onClick() { toast(it.toString()) }
                  view.onClick { toast(it.toString()) }


                  All of those forms are correct (compiler will not fail), but in Kotlin Style Guide you'll find following statement:




                  If a call takes a single lambda, it should be passed outside of
                  parentheses whenever possible.




                  @see https://kotlinlang.org/docs/reference/coding-conventions.html#lambda-formatting



                  That's why IntellJ shows warning. You can click alt + enter and IntellJ should show correct solution, or just move lambda out of parentheses. And if labda is only argument remove parentheses also.
                  When lambda have to be in parentheses? Only when it is not last parameter in function.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Nov 19 '18 at 14:00









                  CililingCililing

                  464211




                  464211























                      1














                      As for your immediate problem, you just have to write it like this:



                      profile.sortedWith(Comparator { profile1, profile2 ->
                      if (profile1.age > profile2.age) return@Comparator 1
                      if (profile1.age < profile2.age) return@Comparator -1
                      return@Comparator 0
                      }
                      )


                      However, the code still has several layers of unneeded verbosity. Here are some ways to make it both more concise and more readable.





                      1. Remove the return statement:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        if (profile1.age > profile2.age) 1
                        else if (profile1.age < profile2.age) -1
                        else 0
                        })



                      2. Use when instead of an if-else cascade:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        when {
                        profile1.age > profile2.age -> 1
                        profile1.age < profile2.age -> -1
                        else -> 0
                        }
                        })



                      3. use Int.compareTo:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        profile1.age.compareTo(profile2.age)
                        }



                      4. use compareBy:



                        profile.sortedWith(compareBy(Profile::age))



                      5. Don't use the general sortedWith when all you need is sortedBy:



                        profile.sortedBy(Profile::age)







                      share|improve this answer
























                      • or better (I think) .sortedBy { it.age }

                        – forpas
                        Nov 19 '18 at 15:06
















                      1














                      As for your immediate problem, you just have to write it like this:



                      profile.sortedWith(Comparator { profile1, profile2 ->
                      if (profile1.age > profile2.age) return@Comparator 1
                      if (profile1.age < profile2.age) return@Comparator -1
                      return@Comparator 0
                      }
                      )


                      However, the code still has several layers of unneeded verbosity. Here are some ways to make it both more concise and more readable.





                      1. Remove the return statement:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        if (profile1.age > profile2.age) 1
                        else if (profile1.age < profile2.age) -1
                        else 0
                        })



                      2. Use when instead of an if-else cascade:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        when {
                        profile1.age > profile2.age -> 1
                        profile1.age < profile2.age -> -1
                        else -> 0
                        }
                        })



                      3. use Int.compareTo:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        profile1.age.compareTo(profile2.age)
                        }



                      4. use compareBy:



                        profile.sortedWith(compareBy(Profile::age))



                      5. Don't use the general sortedWith when all you need is sortedBy:



                        profile.sortedBy(Profile::age)







                      share|improve this answer
























                      • or better (I think) .sortedBy { it.age }

                        – forpas
                        Nov 19 '18 at 15:06














                      1












                      1








                      1







                      As for your immediate problem, you just have to write it like this:



                      profile.sortedWith(Comparator { profile1, profile2 ->
                      if (profile1.age > profile2.age) return@Comparator 1
                      if (profile1.age < profile2.age) return@Comparator -1
                      return@Comparator 0
                      }
                      )


                      However, the code still has several layers of unneeded verbosity. Here are some ways to make it both more concise and more readable.





                      1. Remove the return statement:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        if (profile1.age > profile2.age) 1
                        else if (profile1.age < profile2.age) -1
                        else 0
                        })



                      2. Use when instead of an if-else cascade:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        when {
                        profile1.age > profile2.age -> 1
                        profile1.age < profile2.age -> -1
                        else -> 0
                        }
                        })



                      3. use Int.compareTo:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        profile1.age.compareTo(profile2.age)
                        }



                      4. use compareBy:



                        profile.sortedWith(compareBy(Profile::age))



                      5. Don't use the general sortedWith when all you need is sortedBy:



                        profile.sortedBy(Profile::age)







                      share|improve this answer













                      As for your immediate problem, you just have to write it like this:



                      profile.sortedWith(Comparator { profile1, profile2 ->
                      if (profile1.age > profile2.age) return@Comparator 1
                      if (profile1.age < profile2.age) return@Comparator -1
                      return@Comparator 0
                      }
                      )


                      However, the code still has several layers of unneeded verbosity. Here are some ways to make it both more concise and more readable.





                      1. Remove the return statement:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        if (profile1.age > profile2.age) 1
                        else if (profile1.age < profile2.age) -1
                        else 0
                        })



                      2. Use when instead of an if-else cascade:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        when {
                        profile1.age > profile2.age -> 1
                        profile1.age < profile2.age -> -1
                        else -> 0
                        }
                        })



                      3. use Int.compareTo:



                        profile.sortedWith(Comparator { profile1, profile2 ->
                        profile1.age.compareTo(profile2.age)
                        }



                      4. use compareBy:



                        profile.sortedWith(compareBy(Profile::age))



                      5. Don't use the general sortedWith when all you need is sortedBy:



                        profile.sortedBy(Profile::age)








                      share|improve this answer












                      share|improve this answer



                      share|improve this answer










                      answered Nov 19 '18 at 14:59









                      Marko TopolnikMarko Topolnik

                      146k19197323




                      146k19197323













                      • or better (I think) .sortedBy { it.age }

                        – forpas
                        Nov 19 '18 at 15:06



















                      • or better (I think) .sortedBy { it.age }

                        – forpas
                        Nov 19 '18 at 15:06

















                      or better (I think) .sortedBy { it.age }

                      – forpas
                      Nov 19 '18 at 15:06





                      or better (I think) .sortedBy { it.age }

                      – forpas
                      Nov 19 '18 at 15:06


















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