使用示例在Java中设置 contains() 方法
Java.util.Set.contains() 方法用于检查特定元素是否存在于 Set 中。所以基本上它用于检查 Set 是否包含任何特定元素。
句法:
boolean contains(Object element)
参数:参数元素是Set类型。这是需要测试的元素是否存在于集合中。
返回值:如果元素存在于集合中,则该方法返回 true,否则返回 False。
下面的程序说明了Java.util.Set.contains() 方法:
// Java code to illustrate Set.contains() method
import java.io.*;
import java.util.*;
public class HashSetDemo {
public static void main(String args[])
{
// Creating an empty Set
Set set = new HashSet();
// Using add() method to add elements into the Set
set.add("Welcome");
set.add("To");
set.add("Geeks");
set.add("4");
set.add("Geeks");
// Displaying the Set
System.out.println("Set: " + set);
// Check for "Geeks" in the set
System.out.println("Does the Set contains 'Geeks'? "
+ set.contains("Geeks"));
// Check for "4" in the set
System.out.println("Does the Set contains '4'? "
+ set.contains("4"));
// Check if the Set contains "No"
System.out.println("Does the Set contains 'No'? "
+ set.contains("No"));
}
}
输出:
Set: [4, Geeks, Welcome, To]
Does the Set contains 'Geeks'? true
Does the Set contains '4'? true
Does the Set contains 'No'? false
参考:https: Java Java.lang.Object)