Kotlin Reference (七) feature: Range

KotLin 相关文档

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官方在线Reference
kotlin-docs.pdf
Kotlin for android Developers 中文翻译
Kotlin开发工具集成，相关平台支持指南
Kotlin开源项目与Libraries
Kotlin开源项目、资源、书籍及课程搜索平台
Google’s sample projects written in Kotlin
Kotlin and Android

 

Range

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Range 范围对象，可看成是一组元素的集合。
有三个类型：IntRange、LongRange、CharRange
它们分别主要实现了 IntProgression、LongProgression、CharProgression

 

示例

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以下示例了Range对象的一些操作：

使用循环操作；非循环直接使用函数遍历；
step、until、downTo、first、last、all 等一些关键字与函数用法

package com.stone.features/** * desc  : * author: stone * email : [e-mail] * time  : 13/06/2017 10 00 */object RangeAction {    fun range1() {        for (x in 1..5) {//include 5            print("stone--range1-->$x\t")        }        println()    }    fun range2() {        for (x in 0..10 step 2) {//step2 ==> x+=2            print("stone--range2-->$x\t")        }        println()    }    fun range3() {        for (x in 0 until 10 step 2) {//until 10 ==> not include 10            print("stone--range3-->$x\t")        }        println()    }    fun range4() {        for (x in 10 downTo 0 step 2) {//downTo 0 ==> >=0            print("stone--range4-->$x\t")        }        println()    }    fun range5() {        val range = (10 downTo 0 step 2)        println("stone--range5-->${range.first}\t${range.last}\t${range.step}\t${range.isEmpty()}")        for (x in range.step(3)) {//step(set:Int) ==> change source step        }        val check = range.all { it  >= 0 } //all match fun expression        println("stone--range5-->${range.step(3)}》$check ${range.max()} ${range.count()}")        /*        range type is IntProgression        other type : CharProgression  LongProgression         */        print("stone--range5-->")        for (c in 'a'..'z') {            print("$c ")        }        println()        for (x in 0L until 10L) {        }    }    fun range6() {        var range = (0 until 10 step 2)        print("stone--range6-->")        //Spliterator (java8) 分割迭代  递归的将集合 分割成更小的集合 进行迭代， 当不可再分时 返回null        range.spliterator().trySplit().forEachRemaining { print("$it ") } //"it" refer to the element of collection        println()        print("stone--range6-->reverse-->")        range = range.reversed()        range.filter { i -> i > 2 }.map { it / 1.8 }.forEach({ print(String.format("%.2f ", it)) })        println()//        range.forEach(::println) //method reference    }    fun range7() {        var range1:IntRange = 1.rangeTo(110)        var range2:LongRange = 1L.rangeTo(110L)        var range3 = 10.downTo(1)        var range4 = 10.until(20)    }}fun main(args: Array<String>) {    RangeAction.range1()    RangeAction.range2()    RangeAction.range3()    RangeAction.range4()    RangeAction.range5()    RangeAction.range6()}