Scala中常见的容器 Map

旧城等待， 2022-09-25 00:21 168阅读 0赞

Map(映射)是一种可迭代的键值对（key/value）结构。

所有的值都可以通过键来获取。

Map 中的键都是唯一的。

Map 也叫哈希表（Hash tables）。

Map 有两种类型，可变与不可变，区别在于可变对象可以修改它，而不可变对象不可以。

默认情况下 Scala 使用不可变 Map。如果你需要使用可变集合，你需要显式的引入 **import scala.collection.mutable.Map** 类

在 Scala 中 你可以同时使用可变与不可变 Map，不可变的直接使用 Map，可变的使用 mutable.Map。以下实例演示了不可变 Map 的应用：

// 空哈希表，键为字符串，值为整型
    var A:Map[Char,Int] = Map()
    
    // Map 键值对演示
    val colors = Map("red" -> "#FF0000", "azure" -> "#F0FFFF")

定义 Map 时，需要为键值对定义类型。如果需要添加 key-value 对，可以使用 + 号，如下所示：

A += ('I' -> 1)
    A += ('J' -> 5)
    A += ('K' -> 10)
    A += ('L' -> 100)

## Map 基本操作 ##

Scala Map 有三个基本操作：

### 实例 ###

以下实例演示了以上三个方法的基本应用：

object Test {
       
       def main(args: Array[String]) {
       
          val colors = Map("red" -> "#FF0000",
                           "azure" -> "#F0FFFF",
                           "peru" -> "#CD853F")
    
          val nums: Map[Int, Int] = Map()
    
          println( "colors 中的键为 : " + colors.keys )
          println( "colors 中的值为 : " + colors.values )
          println( "检测 colors 是否为空 : " + colors.isEmpty )
          println( "检测 nums 是否为空 : " + nums.isEmpty )
       }
    }

执行以上代码，输出结果为：

$ scalac Test.scala 
    $ scala Test
    colors 中的键为 : Set(red, azure, peru)
    colors 中的值为 : MapLike(#FF0000, #F0FFFF, #CD853F)
    检测 colors 是否为空 : false
    检测 nums 是否为空 : true

--------------------

## Map 合并 ##

你可以使用 **++** 运算符或 **Map.++()** 方法来连接两个 Map，Map 合并时会移除重复的 key。以下演示了两个 Map 合并的实例:

object Test {
       
       def main(args: Array[String]) {
       
          val colors1 = Map("red" -> "#FF0000",
                            "azure" -> "#F0FFFF",
                            "peru" -> "#CD853F")
          val colors2 = Map("blue" -> "#0033FF",
                            "yellow" -> "#FFFF00",
                            "red" -> "#FF0000")
    
          //  ++ 作为运算符
          var colors = colors1 ++ colors2
          println( "colors1 ++ colors2 : " + colors )
    
          //  ++ 作为方法
          colors = colors1.++(colors2)
          println( "colors1.++(colors2)) : " + colors )
    
       }
    }

执行以上代码，输出结果为：

$ scalac Test.scala 
    $ scala Test
    colors1 ++ colors2 : Map(blue -> #0033FF, azure -> #F0FFFF, peru -> #CD853F, yellow -> #FFFF00, red -> #FF0000)
    colors1.++(colors2)) : Map(blue -> #0033FF, azure -> #F0FFFF, peru -> #CD853F, yellow -> #FFFF00, red -> #FF0000)

--------------------

## 输出 Map 的 keys 和 values ##

以下通过 foreach 循环输出 Map 中的 keys 和 values：

执行以上代码，输出结果为：

$ scalac Test.scala 
    $ scala Test
    Key = runoob Value = http://www.runoob.com
    Key = baidu Value = http://www.baidu.com
    Key = taobao Value = http://www.taobao.com

--------------------

## 查看 Map 中是否存在指定的 Key ##

你可以使用 **Map.contains** 方法来查看 Map 中是否存在指定的 Key。实例如下：

object Test {
       
       def main(args: Array[String]) {
       
          val sites = Map("runoob" -> "http://www.runoob.com",
                           "baidu" -> "http://www.baidu.com",
                           "taobao" -> "http://www.taobao.com")
    
          if( sites.contains( "runoob" )){
       
               println("runoob 键存在，对应的值为 :"  + sites("runoob"))
          }else{
       
               println("runoob 键不存在")
          }
          if( sites.contains( "baidu" )){
       
               println("baidu 键存在，对应的值为 :"  + sites("baidu"))
          }else{
       
               println("baidu 键不存在")
          }
          if( sites.contains( "google" )){
       
               println("google 键存在，对应的值为 :"  + sites("google"))
          }else{
       
               println("google 键不存在")
          }
       }
    }

执行以上代码，输出结果为：

$ scalac Test.scala 
    $ scala Test
    runoob 键存在，对应的值为 :http://www.runoob.com
    baidu 键存在，对应的值为 :http://www.baidu.com
    google 键不存在

--------------------

## Scala Map 方法 ##

下表列出了 Scala Map 常用的方法：

<table style="border:0px; margin:4px 0px; padding:0px; border-collapse:collapse; width:729px; color:rgb(51,51,51); font-family:&quot;Open Sans&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,STHeiti,&quot;Microsoft Yahei&quot;,sans-serif; font-size:12px"> 
 <tbody style="border:0px; margin:0px; padding:0px"> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <th style="border:1px solid rgb(85,85,85); margin:0px; padding:3px; color:rgb(255,255,255); vertical-align:top; text-align:left; width:30px; background-color:rgb(85,85,85)"> 序号</th> 
 <th style="border:1px solid rgb(85,85,85); margin:0px; padding:3px; color:rgb(255,255,255); vertical-align:top; text-align:left; width:685px; background-color:rgb(85,85,85)"> 方法及描述</th> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 1</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def ++(xs: Map[(A, B)]): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回一个新的 Map，新的 Map xs 组成 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 2</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def -(elem1: A, elem2: A, elems: A*): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回一个新的 Map, 移除 key 为 elem1, elem2 或其他 elems。 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 3</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def --(xs: GTO[A]): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回一个新的 Map, 移除 xs 对象中对应的 key </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 4</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def get(key: A): Option[B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回指定 key 的值 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 5</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def iterator: Iterator[(A, B)] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 创建新的迭代器，并输出 key/value 对 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 6</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def addString(b: StringBuilder): StringBuilder <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 将 Map 中的所有元素附加到StringBuilder，可加入分隔符 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 7</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def addString(b: StringBuilder, sep: String): StringBuilder <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 将 Map 中的所有元素附加到StringBuilder，可加入分隔符 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 8</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def apply(key: A): B <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回指定键的值，如果不存在返回 Map 的默认方法 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 9</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def clear(): Unit <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 清空 Map </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 10</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def clone(): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 从一个 Map 复制到另一个 Map </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 11</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def contains(key: A): Boolean <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 如果 Map 中存在指定 key，返回 true，否则返回 false。 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 12</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def copyToArray(xs: Array[(A, B)]): Unit <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 复制集合到数组 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 13</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def count(p: ((A, B)) =&gt; Boolean): Int <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 计算满足指定条件的集合元素数量 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 14</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def default(key: A): B <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 定义 Map 的默认值，在 key 不存在时返回。 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 15</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def drop(n: Int): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回丢弃前n个元素新集合 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 16</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def dropRight(n: Int): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回丢弃最后n个元素新集合 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 17</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def dropWhile(p: ((A, B)) =&gt; Boolean): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 从左向右丢弃元素，直到条件p不成立 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 18</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def empty: Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回相同类型的空 Map </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 19</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def equals(that: Any): Boolean <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 如果两个 Map 相等(key/value 均相等)，返回true，否则返回false </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 20</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def exists(p: ((A, B)) =&gt; Boolean): Boolean <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 判断集合中指定条件的元素是否存在 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 21</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def filter(p: ((A, B))=&gt; Boolean): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回满足指定条件的所有集合 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 22</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def filterKeys(p: (A) =&gt; Boolean): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回符合指定条件的的不可变 Map </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 23</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def find(p: ((A, B)) =&gt; Boolean): Option[(A, B)] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 查找集合中满足指定条件的第一个元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 24</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def foreach(f: ((A, B)) =&gt; Unit): Unit <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 将函数应用到集合的所有元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 25</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def init: Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回所有元素，除了最后一个 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 26</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def isEmpty: Boolean <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 检测 Map 是否为空 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 27</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def keys: Iterable[A] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回所有的key/p&gt; </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 28</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def last: (A, B) <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回最后一个元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 29</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def max: (A, B) <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 查找最大元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 30</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def min: (A, B) <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 查找最小元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 31</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def mkString: String <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 集合所有元素作为字符串显示 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 32</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def product: (A, B) <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回集合中数字元素的积。 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 33</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def remove(key: A): Option[B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 移除指定 key </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 34</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def retain(p: (A, B) =&gt; Boolean): Map.this.type <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 如果符合满足条件的返回 true </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 35</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def size: Int <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回 Map 元素的个数 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 36</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def sum: (A, B) <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回集合中所有数字元素之和 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 37</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def tail: Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回一个集合中除了第一元素之外的其他元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 38</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def take(n: Int): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回前 n 个元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 39</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def takeRight(n: Int): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回后 n 个元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 40</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def takeWhile(p: ((A, B)) =&gt; Boolean): Map[A, B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回满足指定条件的元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 41</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def toArray: Array[(A, B)] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 集合转数组 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 42</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def toBuffer[B &gt;: A]: Buffer[B] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回缓冲区，包含了 Map 的所有元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 43</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def toList: List[A] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回 List，包含了 Map 的所有元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 44</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def toSeq: Seq[A] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回 Seq，包含了 Map 的所有元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 45</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def toSet: Set[A] <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回 Set，包含了 Map 的所有元素 </td> 
 </tr> 
 <tr style="border:0px; margin:0px; padding:0px; background-color:rgb(246,244,240)"> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> 46</td> 
 <td style="border:1px solid rgb(212,212,212); margin:0px; padding:7px 5px; font-size:1em; vertical-align:top"> <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> def toString(): String <p style="border:0px; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px; line-height:2em; font-family:&quot;Microsoft Yahei&quot;,&quot;Helvetica Neue&quot;,Helvetica,Arial,sans-serif"> 返回字符串对象 </td> 
 </tr> 
 </tbody> 
</table>