Kotlin 基础教程之数组容器
Kotlin基础教程之数组容器
Arrays
Kotlin标准库提供了arrayOf()创建数组，**ArrayOf创建特定类型数组
valarray=arrayOf(1,2,3)
valcountries=arrayOf("UK","Germany","Italy")
valnumbers=intArrayOf(10,20,30)
valarray1=Array(10,{k->k*k})
vallongArray=emptyArray()
valstudentArray=Array(2)
studentArray[0]=Student("james")
和Java不一样，Kotlin的数组是容器类，提供了ByteArray,CharArray,ShortArray,IntArray,LongArray,BooleanArray,FloatArray,andDoubleArray。
Lists
List是有序容器，Kotlin标准库通过listOf()创建list
valintList:List=listOf(20,5,10) valemptyList:List =emptyList () valnonNulls:List =listOfNotNull (null,"a","b","c") valdoubleList:ArrayList =arrayListOf(84.88,100.25,999.99)
其中，intList,emptyList,nonNulls是只读的实例，要修改这些list，需要进行类型转换
(intListasAbstractList).set(0,30) (nonNullsasjava.util.ArrayList).addAll(arrayOf("x","y"))
Maps
Map是
valmap=mapOf("a"to1,"b"to2,"c"to3)
valvalue=map.get(b)
valstates:MutableMap=mutableMapOf("AL"to"Alabama",
"AK"to"Alaska","AZ"to"Arizona")
valcustomers:java.util.HashMap=hashMapOf(1to
Customer("Dina","Kreps",1),2toCustomer("Andy","Smith",2))
vallinkedHashMap:java.util.LinkedHashMap=
linkedMapOf("red"to"#FF0000","azure"to"#F0FFFF","white"to"#FFFFFF")
valsortedMap:java.util.SortedMap=sortedMapOf(4to"d",
1to"a",3to"c",2to"b")
Sets
Set是没有重复项的容器，Kotlin提供setOf创建Set
valintSet:Set=setOf(1,21,21,2,6,3,2)//1,21,2,6,3 valhashSet:java.util.HashSet =hashSetOf( Book("JulesVerne","AroundtheWorldin80DaysPaperback",2014,"978-1503215153"), Book("JulesVerne","AroundtheWorldin80DaysPaperback",2014,"978-1503215153")) valsortedIntegers:java.util.TreeSet =sortedSetOf(11,0,9,11,9,8)
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