第七节：定长与变长Array

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)=1 scala> numArray(11)=1 java.lang.ArrayIndexOutOfBoundsException: 11 ... 29 elided //赋值报错 scala> numArray res8: 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.ArrayBuffer import scala.collection.mutable.ArrayBuffer // 定义一个边长的Int 形Array scala> var numArray = ArrayBuffer[Int]() numArray: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer() // 在0处插入1 scala> numArray.insert(0,1) scala> numArray res14: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1) // 在0处 插入 1，2，3 scala> numArray.insert(0,1,2,3) scala> numArray res16: 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> numArray res18: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(2, 3, 1) // 转成定长数组 scala> numArray.toArray res19: 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> strArray res24: 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> strArray res27: scala.collection.mutable.ArrayBuffer[String] = ArrayBuffer(erhuan) // 转成定长 scala> strArray.toArray res25: Array[String] = Array(erhuan)