Scala set函数及示例
ScalaSet函数
Scala编程语言具有许多在Scala中的集合上运行的功能。在有关Scala的本教程中，我们学习了将在Scala中的集合上运行的函数。
集合是一种特殊类型的集合，其中包含所有唯一元素。在Scala中，许多功能可用于在Scala中操作数据。
让我们在Scala中查看其中一些功能，
1）在集合中添加元素（在可变集合上）
在Scala中，某些功能可用于覆盖可变集合以执行加法运算。
+=：此运算符用于将新元素添加到不可变集合中的可变集合中。
++==：此运算符用于将新元素添加到可变集合。
add()：此方法用于将新元素添加到不可变集合中的可变集合中。
让我们举几个例子来了解代码的工作原理，
import scala.collection.mutable._
object Main
{
def main(args: Array[String])
{
var myBikes = Set("Ninja 300" , "Thunderbird 350", "Dominar 400")
println("My bike collection is : ") println(myBikes)
print("Adding a new bike to my collection, ")
myBikes += "Continental GT"
println("My bike collection now is: ") println(myBikes)
println("Adding some new bikes to my collection, ")
myBikes ++== List("Bajaj Platina", "Splender")
println("My bike collection now is: ") println(myBikes)
print("Adding a new bike to my collection, ")
myBikes.add("Hayabusa")
println("My bike collection now is: ") println(myBikes)
}
}输出结果
My bike collection is : HashSet(Thunderbird 350, Dominar 400, Ninja 300) Adding a new bike to my collection, My bike collection now is: HashSet(Thunderbird 350, Continental GT, Dominar 400, Ninja 300) Adding some new bikes to my collection, My bike collection now is: HashSet(Splender, Bajaj Platina, Dominar 400, Ninja 300, Thunderbird 350, Continental GT) Adding a new bike to my collection, My bike collection now is: HashSet(Splender, Hayabusa, Bajaj Platina, Dominar 400, Ninja 300, Thunderbird 350, Continental GT)
2）在集合中添加元素（在不可变元素上）
对于不可变的集合，我们不能将元素添加到现有集合中。但是我们可以添加具有不可变集合的元素，并将其存储到新变量中。对于这两个运算符可以使用，
+：此运算符用于将一个元素添加到集合中，然后将其存储到另一个变量中。
++：此运算符用于将多个元素添加到集合中，然后将该总和存储到另一个变量中。
示例
import scala.collection.immutable._
object Main
{
def main(args: Array[String])
{
val myBikes = Set("R1" , "Thunderbird" , "GS390")
val FBikes = Set("Bullet 350", "Continental GT" , "K1000")
println("My Bike collection: ")
println(myBikes)
println("My friends Bike collection: ")
println(FBikes)
println("Adding one more bike to friends collection ")
var FBikes2 = FBikes + "Ninja 300"
println("My friends Bike collection now is: ")
println(FBikes2)
println("Adding more bikes to my collection ")
var myBikes2 = myBikes ++ List("CBR 1000R" ,"R1100R" )
println("My friends Bike collection now is: ")
println(myBikes2)
println("Our collection togather has: ")
var bike = myBikes2 ++ FBikes2 println(bike)
}
}输出结果
My Bike collection: Set(R1, Thunderbird, GS390) My friends Bike collection: Set(Bullet 350, Continental GT, K1000) Adding one more bike to friends collection My friends Bike collection now is: Set(Bullet 350, Continental GT, K1000, Ninja 300) Adding more bikes to my collection My friends Bike collection now is: HashSet(R1100R, GS390, Thunderbird, R1, CBR 1000R) Our collection togather has: HashSet(R1100R, Ninja 300, GS390, K1000, Continental GT, Thunderbird, Bullet 350, R1, CBR 1000R)
3）从集合中删除元素（在可变集合上）
在Scala编程语言中，从集合中删除元素是有效的。有可用于执行任务的运算符和方法。
-=：此运算符用于从集合中删除单个元素。
-=：此运算符用于从集合中删除多个元素。
方法retain()，clear()，remove()用于删除可变集合从可变集合中的元素。
示例
import scala.collection.mutable._
object Main
{
def main(args: Array[String])
{
var myBikes = Set("Ninja 300" , "Thunderbird 350", "Dominar 400", "Continental GT", "S1000RR")
println("My bike collection is: ") println(myBikes)
println("Removing dominar400 from my collection : ")
myBikes -= "Dominar 400"
println("My Collection is : ") println(myBikes)
println("Removing few more bikes from my collection : ")
myBikes --== List("S1000RR" , "Ninja 300")
println("My Collection is : ") println(myBikes)
}
}输出结果
My bike collection is: HashSet(Dominar 400, Ninja 300, Thunderbird 350, Continental GT, S1000RR) Removing dominar400 from my collection : My Collection is : HashSet(Ninja 300, Thunderbird 350, Continental GT, S1000RR) Removing few more bikes from my collection : My Collection is : HashSet(Thunderbird 350, Continental GT)
4）从集合中删除元素（在不可变集合上）
对于不可变集合，我们通常无法从集合中删除元素。我们需要将它们从集合中删除，然后将更新的集合存储到新的内存位置。运算符-和-对于从集合中删除元素有效。
示例
import scala.collection.immutable._
object Main
{
def main(args: Array[String])
{
val myBikes = Set("Ninja 300" , "Thunderbird 350", "Dominar 400", "Continental GT", "S1000RR")
println("My bike collection is : ") println(myBikes)
println("Removing dominar400 from my collection: ")
val myBikes2 = myBikes - "Dominar 400"
println("My Collection is: ")
println(myBikes2)
println("Removing few more bikes from my collection: ")
val myBikes3 = myBikes2 -- List("S1000RR" , "Ninja 300")
println("My Collection is: ")
println(myBikes3)
}
}输出结果
My bike collection is : HashSet(Ninja 300, Continental GT, Dominar 400, S1000RR, Thunderbird 350) Removing dominar400 from my collection: My Collection is: HashSet(Ninja 300, Continental GT, S1000RR, Thunderbird 350) Removing few more bikes from my collection: My Collection is: HashSet(Continental GT, Thunderbird 350)