播放 Scala 更改自定义列表项值
Play Scala changing custom List item value
在我的 Play Framework Scala
项目中,我有一个 custom List
。我需要的一些操作 change/replace 带有 another value
的自定义列表项值。Scala
没有Java
没有像下面这样的方法
List<Int> testList = new ArrayList<Int>();
testList.get(0)// get the testList 0 th value
我需要的
case class ImageGrid(
image_id: Int,
image_name: String,
image_desc: String
)
val ImageGridList:List[ImageGrid] = //based on some DB Query I set values
我怎样才能 change/Replace 0th
或 1st
ImageGridList's
image_name
或 image_desc
的位置
使用scala.collection.mutable.ArrayBuffer代替列表
val list = scala.collection.mutable.ArrayBuffer(1,2,3,4)
按索引位置设置值:
list(0)=5
您可以使用可变的ArrayBuffer,这里是示例代码;
scala> import scala.collection._
import scala.collection._
scala> case class ImageGrid(
| image_id: Int,
| image_name: String,
| image_desc: String
| )
defined class ImageGrid
scala> val imageGridList = mutable.Buffer[ImageGrid](ImageGrid(1,"img1","img2"))
imageGridList: scala.collection.mutable.Buffer[ImageGrid] = ArrayBuffer(ImageGrid(1,img1,img2))
scala> imageGridList(0) = ImageGrid(1,"img name changed","img2")
scala> imageGridList
res1: scala.collection.mutable.Buffer[ImageGrid] = ArrayBuffer(ImageGrid(1,img name changed,img2))
要将现有 List 转换为 ArrayBuffer,请使用 toBuffer
在我的 Play Framework Scala
项目中,我有一个 custom List
。我需要的一些操作 change/replace 带有 another value
的自定义列表项值。Scala
没有Java
没有像下面这样的方法
List<Int> testList = new ArrayList<Int>();
testList.get(0)// get the testList 0 th value
我需要的
case class ImageGrid(
image_id: Int,
image_name: String,
image_desc: String
)
val ImageGridList:List[ImageGrid] = //based on some DB Query I set values
我怎样才能 change/Replace 0th
或 1st
ImageGridList's
image_name
或 image_desc
使用scala.collection.mutable.ArrayBuffer代替列表
val list = scala.collection.mutable.ArrayBuffer(1,2,3,4)
按索引位置设置值:
list(0)=5
您可以使用可变的ArrayBuffer,这里是示例代码;
scala> import scala.collection._
import scala.collection._
scala> case class ImageGrid(
| image_id: Int,
| image_name: String,
| image_desc: String
| )
defined class ImageGrid
scala> val imageGridList = mutable.Buffer[ImageGrid](ImageGrid(1,"img1","img2"))
imageGridList: scala.collection.mutable.Buffer[ImageGrid] = ArrayBuffer(ImageGrid(1,img1,img2))
scala> imageGridList(0) = ImageGrid(1,"img name changed","img2")
scala> imageGridList
res1: scala.collection.mutable.Buffer[ImageGrid] = ArrayBuffer(ImageGrid(1,img name changed,img2))
要将现有 List 转换为 ArrayBuffer,请使用 toBuffer