斯卡拉从地图数组得到数组 [英] Scala get Array from array in Map

问题描述

我在新斯卡拉，有地图：（这样也好，因为我获得巨大的地图像这样从蒙戈）

i new at scala, there is the Map: (it so, cos i get huge Map like this from mongo)

val test = Map(
      "temp" -> Array( 1,
        Array(
          1, "kisa"
        )
      )
    )

我怎样才能获得KISA？

How i can get "kisa" ?

推荐答案

所以......让我解释，

So... let me explain,

val test = Map(
  "temp" -> Array( 1,
    Array(
      1, "kisa"
    )
  )
)

现在测试是 scala.collection.immutable.Map [字符串，数组[任何] 这意味着地图从字符串到数组[任何] 。

所以...获得与主要关联值 - TEMP，您

So... to get value associated with key - "temp", you do

val tempVal = test( "temp" )

现在， tempVal 的类型为数组[任何] 键，其值为阵列（1，阵列（1，KISA））

Now, tempVal is of type Array[ Any ] and its value is Array( 1, Array( 1, kisa ) )

我们要的是第二个（指数= 1）进入该数组中

What we want is the second ( index = 1 ) entry in this array.

val secondEntry = tempVal( 1 )

现在... secondEntry 的类型为任何键，其值为阵列（1 ，克萨） ...我们无法获得克萨现在......首先，我们必须从施放此的任何到数组[任何] 。

Now... secondEntry has type Any and its value is Array( 1, Kisa )... we can not obtain Kisa now... first we have to cast this from Any to Array[ Any ].

val secondEntryArray = secondEntry.asInstanceOf[ Array[ Any ] ]

现在... secondEntryArray 的类型为数组[任何] 键，其值为阵列（1，KISA）

Now... secondEntryArray is of type Array[ Any ] and its value is Array( 1, kisa )

现在，我们必须从这个数组第二个条目，

Now, we have to get second entry from this array,

val kisaVal = secondEntryArray( 1 )

现在... kisaVal 的类型为任何键，其值为 KISA 。你知道，这是一个字符串你可能想把它当作一个字符串 ...所以让类型强制转换为一个字符串，

Now... kisaVal has type Any and its value is kisa. You know that it is a String and you probably want it as a String... so lets type-cast it to a String,

val kisaString = kisaVal.asInstanceOf[ String ]

和你做。

要做到这一点只是在同一行......

To do it simply in one line....

val kisa = test( "temp" )( 1 ).asInstanceOf[ Array[ Any ] ]( 1 ).asInstanceOf[ String ]

这篇关于斯卡拉从地图数组得到数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！