Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!
MutableList vs ArrayList¶
MutableList is ArrayList in Kotlin currently.
Create an Empty MutableList¶
Below is the most idiomatical way to create an empty mutable list in Kotlin.
val mutableList = mutableListOf<Int>()
mutableList[]Another way to create an emtpy MutableList.
MutableList < Int > (0, {0})[]Create an MutableList with Initial Values¶
Create a MutableList containing 3 zeros.
val arrList = MutableList < Int > (3, {0})
arrList[0, 0, 0]Create a MutableList with initial values.
val mList = mutableListOf(1, 2, 3)
mList[1, 2, 3]listOf(0, 1, 2) + listOf(3, 4, 5)[0, 1, 2, 3, 4, 5]val list = listOf(0, 1, 2, 3, 4)
list[0, 1, 2, 3, 4]val arrList = mutableListOf(1, 2) + mutableListOf(3, 4)
arrList[1, 2, 3, 4]arrList.lastIndex3arrList.indices0..3arrList.add(1000)Line_31.jupyter-kts (1:9 - 12) Unresolved reference: addval mList1 = mutableListOf(1, 2, 3)
mList1[1, 2, 3]mList1.toCollection(mutableListOf())[1, 2, 3]val mList2 = mList1.toMutableList()nullVerify that mList2 has the same elements as mList1.
mList2 == mList1trueVerify that mList2 is a different object than mList1.
mList2 === mList1falseMethods and Operators¶
addAll¶
val mList = mutableListOf(1, 2, 3)
mList[1, 2, 3]mList.addAll(listOf(4, 5, 6))
mList[1, 2, 3, 4, 5, 6]val mList1 = mList.subList(1, 3)
mList1[2, 3]mList1.add(100)
mList1[2, 3, 100]mList[1, 2, 3, 100]list.subList(1, 3)[1, 2]val mList2 = mList.slice(1 until 3)
mList2[2, 3]val mList3 = mList2 + mutableListOf(1000, 2000)
mList3[2, 3, 1000, 2000]list.take(3)[0, 1, 2]list.takeLast(2)[3, 4]data class is preferred over Tuple-like data.
ceil(2.3)3.0References¶
https://
https://
https://
https://