Question

当我在初始化时设置不可变的hashmap内容时：

var result_tags=HashMap[String,Int]()
    result_tags=("video"->0,"game"->0,"news"->0,"ee"->0,"sport"->0,
  "shop"->0,"ju"->0,"story"->0,"pho"->0,"con"->0,"live"->0,"life"->0,"soft"->0,"hire"->0,"car"->0,
  "mm"->0,"mus"->0,"mob"->0,"male"->0,"heal"->0, "sca"->0,"bank"->0,"mail"->0,"cool"->0,"pict"->0, "dl"->0)

它给了我错误：

too many elements for tuple:26,allowed:22

这意味着元组的最大数量为22.我知道->用于创建元组。是否有其他方法来初始化hashmap而没有其元素的限制数。

Answer 1

您实际在做的是初始化巨型Tuple类型并尝试将其分配给类型为result_tags的{{1}}变量，即使元组大小不会超过最大尺寸。

因此，关于元组的错误并不是指您使用的HashMap语法，而是指->列表中的元素数。即使你这样写，你也会得到同样的错误：

(...)

其次，在你的情况下你应该这样做：

(("video", 0), ("game", 0), ..., ("dl", 0))

（注意我省略了类型信息，因为Scala会为你推断出类型。）

var result_tags = HashMap("video" -> 0, "game" -> 0, ..., "dl" -> 0)语法在Scala中完全不同，因为它初始化了一个元组类型。每个此类声明都转换为(a1, a2, ..., aN)类型，其中最大大小为22.因此，Scala库实际上有22个不同的TupleN类，从Tuple到Tuple1。

第三，你的风格可以使用一些修正

您应该更喜欢Tuple22
您应该更喜欢不可变变量，这意味着scala.collection.Map而不是val
不太重要，但变量名称最好是camelCased，因此var

Answer 2

只是

var result_tags = Map("video"->0,"game"->0,"news"->0,"ee"->0,"sport"->0,
  "shop"->0,"ju"->0,"story"->0,"pho"->0,"con"->0,"live"->0,"life"->0,"soft"->0,"hire"->0,"car"->0,
  "mm"->0,"mus"->0,"mob"->0,"male"->0,"heal"->0, "sca"->0,"bank"->0,"mail"->0,"cool"->0,"pict"->0, "dl"->0)

Answer 3

这是在Scala中初始化Map的方法

地图初始化

import scala.collection.immutable.Map

val result_tags = Map("video" -> 0, "game" -> 0, "news" -> 0, "ee" -> 0, "sport" -> 0,
      "shop" -> 0, "ju" -> 0, "story" -> 0, "pho" -> 0, "con" -> 0, "live" -> 0, "life" -> 0, "soft" -> 0, "hire" -> 0, "car" -> 0,
      "mm" -> 0, "mus" -> 0, "mob" -> 0, "male" -> 0, "heal" -> 0, "sca" -> 0, "bank" -> 0, "mail" -> 0, "cool" -> 0, "pict" -> 0, "dl" -> 0)

HashMap初始化

import scala.collection.immutable.HashMap

val result_tags = HashMap("video" -> 0, "game" -> 0, "news" -> 0, "ee" -> 0, "sport" -> 0,
      "shop" -> 0, "ju" -> 0, "story" -> 0, "pho" -> 0, "con" -> 0, "live" -> 0, "life" -> 0, "soft" -> 0, "hire" -> 0, "car" -> 0,
      "mm" -> 0, "mus" -> 0, "mob" -> 0, "male" -> 0, "heal" -> 0, "sca" -> 0, "bank" -> 0, "mail" -> 0, "cool" -> 0, "pict" -> 0, "dl" -> 0)

Answer 4

您还可以使用immutable.HashMap类中的var myDiv = document.createElement("div"); var imgPath = "http://127.0.0.1:8888/service/file/download/hd1.jpg?code=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6IjU3ZTYwOTMyOWE5MmQ0MGEwNzk5YzZmYiJ9.H78qRMZNOfWxVnA8mbybQD5Yh1ZBVRhRQgzFNmJMVvs"; $(myDiv).css("background-image", "url(" + imagPath + ")");方法来实现您尝试执行的操作：

来自scala doc：

初始化hashmap时元素太多

4 个答案: