Array 数组

初始化数组 

package main

object Test {

  def main(args: Array[String]): Unit = {

    val array = Array(1, 2, 3, 4, 5);
    println(array); //[I@3c5a99da
    println(array.mkString(" "));
    //1 2 3 4 5

    val array5 = Array(1 to 5: _*);
    println(array5); //[I@43a25848
    println(array5.mkString(" "));
    //1 2 3 4 5    
  }
}

 

数组的长度 

package main

object Test {

  def main(args: Array[String]): Unit = {

    val array = Array(1, 2, 3, 4, 5);
    println(array); //[I@3c5a99da
    println(array.mkString(" "));
    //1 2 3 4 5

    println(array.length); //5

    println(array.size); //5
  }
}

推荐使用：length

调用数组的 size 会产生隐式转换，生成中间包装类，即会产生多余的GC对象。

 

更新数组

package main

object Test {

  def main(args: Array[String]): Unit = {

    val array = Array(1, 2, 3, 4, 5);
    println(array); //[I@3c5a99da
    println(array.mkString(" "));
    //1 2 3 4 5

    array.update(0, 10);
    println(array.mkString(" "));
    //10 2 3 4 5

    array(1) = 200; //简写
    println(array.mkString(" "));
    //10 200 3 4 5
  }
}