Kotlin 集：setOf()

Kotlin Set 接口是一个通用的无序元素集合，它不包含重复的元素。 Kotlin 支持两种类型的集合可变和不可变。
setOf()是不可变的，意味着它只支持只读功能，而mutableSetOf()是可变的，意味着它支持读取和写入这两种功能。

句法：

fun  setOf( vararg elements: T): Set

描述：

• 此函数返回一组新的只读给定元素。
• 元素被迭代，根据它们被存储。

setOf()函数的 Kotlin 程序：

Kotlin

fun main(args: Array)
{
    //declaring a set of strings
    val seta = setOf("Geeks" , "for", "geeks")
    //declaring a set of characters
    val setb = setOf( "G" , "f" , "g" )
    //declaring a set of integers
    val setc = setOf( 1 ,2 , 3 , 4 )
 
    //traversing through a set of strings
    for(item in seta)
        print( item )
    println()
    //traversing through a set of characters
    for(item in setb)
        print( item )
    println()
    //traversing through a set of integers
    for(item in setc)
        print( "$item ")
}

输出：

Geeksforgeeks
Gfg
1 2 3 4 

设置索引 –

使用索引函数 indexOf() ， lastIndexOf() 我们可以获得指定元素的索引。我们还可以使用 elementAt()函数找到某个特定索引处的元素。

Kotlin 使用索引的程序——

科特林

fun main(args: Array) {
 
    val captains = setOf("Kohli","Smith","Root","Malinga","Rohit","Dhawan")
 
    println("The element at index 2 is: "+captains.elementAt(2))
 
    println("The index of element is: "+captains.indexOf("Smith"))
 
    println("The last index of element is: "+captains.lastIndexOf("Rohit"))
}

输出：

The element at index 2 is: Root
The index of element is: 1
The last index of element is: 4 

设置第一个和最后一个元素 -

我们可以使用 first() 和 last() 函数获取集合的第一个和元素。

Kotlin 程序 –

科特林

fun main(args: Array){
    val captains = setOf(1,2,3,4,"Kohli","Smith",
        "Root","Malinga","Rohit","Dhawan")
 
    println("The first element of the set is: "+captains.first())
 
    println("The last element of the set is: "+captains.last())
}

输出：

The first element of the set is: 1
The last element of the set is: Dhawan

设置基础 –

在这里，我们将讨论 count()、max()、min()、sum()、average() 等基本函数。

Kotlin 程序使用基本功能——

科特林

fun main(args: Array) {
 
    val num = setOf(1 ,2, 3, 4, 5, 6, 7, 8)
 
    println("The number of element in the set is: "+num.count())
    println("The maximum element in the set is: "+num.max())
    println("The minimum element in the set is: "+num.min())
    println("The sum of the elements in the set is: "+num.sum())
    println("The average of elements in the set is: "+num.average())
}

输出：

The number of element in the set is: 8
The maximum element in the set is: 8
The minimum element in the set is: 1
The sum of the elements in the set is: 36
The average of elements in the set is: 4.5

contains() 和 containsAll() 函数 –

这两种方法都用于检查集合中是否存在元素？

使用 contains() 和 containsAll()函数的 Kotlin 程序 -

科特林

fun main(args: Array){
    val captains = setOf(1,2,3,4,"Kohli","Smith",
        "Root","Malinga","Rohit","Dhawan")
 
 
    var name = "Dhawan"
    println("The set contains the element $name or not?" +
            "   "+captains.contains(name))
 
    var num = 5
    println("The set contains the element $num or not?" +
            "   "+captains.contains(num))
 
    println("The set contains the given elements or not?" +
            "   "+captains.containsAll(setOf(1,3,"Root")))
}

输出：

The set contains the element Dhawan or not?   true
The set contains the element 5 or not?   false
The set contains the given elements or not?   true 

检查空集的相等性和使用 isEmpty() 函数 -

fun  setOf(): Set

此语法返回特定类型的空集。

使用 isEmpty()函数的 Kotlin 程序 –

科特林

fun main(args: Array) {
    //creating an empty set of strings
    val seta = setOf()
    //creating an empty set of integers
    val setb =setOf()
 
 
    //checking if set is empty or not
    println("seta.isEmpty() is ${seta.isEmpty()}")
 
    // Since Empty sets are equal
 
    //checking if two sets are equal or not
    println("seta == setb is ${seta == setb}")
 
    println(seta) //printing first set
}

输出 ：

seta.isEmpty() is true
seta == setb is true
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