第七节：定长与变长Array

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定长数组

//定义一个长为10 Int 类型数组scala> var numArray = new Array[Int](10)numArray: Array[Int] = Array(0, 0, 0, 0, 0, 0, 0, 0, 0, 0)//定义一个长为10 String 类型数组scala> var strArray = new Array[String](10)strArray: Array[String] = Array(null, null, null, null, null, null, null, null, null, null)// 数组赋值scala> numArray(0)=1scala> numArray(11)=1java.lang.ArrayIndexOutOfBoundsException: 11  ... 29 elided//赋值报错scala> numArrayres8: Array[Int] = Array(1, 0, 0, 0, 0, 0, 0, 0, 0, 0)// 这说明 数组的长度不可变但是值是可变的// 定义数组的同时进行赋值scala> var strArrayinit= Array("erhuan","nolimit")strArrayinit: Array[String] = Array(erhuan, nolimit)

变长数组

变长数组需要导入scala.collection.mutable.ArrayBuffer

// 导入包 scala> import scala.collection.mutable.ArrayBufferimport scala.collection.mutable.ArrayBuffer// 定义一个边长的Int 形Arrayscala> var numArray = ArrayBuffer[Int]()numArray: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer()// 在0处插入1scala> numArray.insert(0,1)scala> numArrayres14: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1)// 在0处 插入 1，2，3scala> numArray.insert(0,1,2,3)scala> numArrayres16: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1, 2, 3, 1)//从0处开始  删除1和数scala> numArray.remove(0,1)scala> numArrayres18: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(2, 3, 1)// 转成定长数组scala> numArray.toArrayres19: Array[Int] = Array(2, 3, 1)

// String 类型变长数组scala> var strArray = ArrayBuffer[String]()strArray: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer()//末尾添加元素scala> strArray+="erhuan"res20: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(erhuan)// 添加集合scala> strArray+=("is","a","man")res21: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(erhuan, is, a, man)//添加任意集合scala> strArray++=Array("tall","1.8")res22: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(erhuan, is, a, man, tall, 1.8)// 删掉末尾2个元素scala> strArray.trimEnd(2)scala> strArrayres24: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(erhuan, is, a, man)// 从1处开始删掉三个scala> strArray.remove(1,3)scala> strArrayres27: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(erhuan)// 转成定长scala> strArray.toArrayres25: Array[String] = Array(erhuan)

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