I have a list of integers, like:
val myList = listOf(3,4,2)
Is there any quick way in Kotlin to sum all the values of the list? or do I have to use a loop?
Thanks.
I have a list of integers, like:
val myList = listOf(3,4,2)
Is there any quick way in Kotlin to sum all the values of the list? or do I have to use a loop?
Thanks.
You can use the .sum()
function to sum all the elements in an array or collection of Byte
, Short
, Int
, Long
, Float
or Double
. (docs)
For example:
val myIntList = listOf(3, 4, 2)
myIntList.sum() // = 9
val myDoubleList = listOf(3.2, 4.1, 2.0)
myDoubleList.sum() // = 9.3
The above answer is correct, as an added answer, if you want to sum some property or perform some action you can use sumBy like this:
sum property:
data class test(val id: Int)
val myTestList = listOf(test(1), test(2),test(3))
val ids = myTestList.sumBy{ it.id } //ids will be 6
sum with an action
val myList = listOf(1,2,3,4,5,6,7,8,9,10)
val addedOne = myList.sumBy { it + 1 } //addedOne will be 65
The above answers are correct but, this can be another way if you also want to sum all integers, double, float inside a list of Objects
list.map { it.duration }.sum()