Java Java.util.Collections.disjoint()用法及代碼示例

java.util.Collections類中提供了java.util.Collections.disjoint()方法。它用於檢查兩個指定的集合是否不相交。更正式地講，如果兩個集合沒有共同的元素，則它們是不相交的。

用法:
public static boolean disjoint(Collection<?> c1, Collection<?> c2)
參數:
c1 - a collection
c2 - a collection
返回:
true if the two specified collections have no elements in common.
Throws:
NullPointerException - if either collection is null.
NullPointerException - if one collection contains a null element and null is not an eligible 
element for the other collection.
ClassCastException - if one collection contains an element that is of a type which is ineligible
 for the other collection.

注意，允許在兩個參數中傳遞相同的集合，在這種情況下，當且僅當集合為空時，該方法才會返回true。

// Java program to demonstrate working of  
// java.utils.Collections.disjoint() 
  
import java.util.*; 
   
public class DisjointDemo 
{ 
    public static void main(String[] args) 
    { 
        // Let us create array list of strings 
        List<String>  mylist1 = new ArrayList<String>(); 
        mylist1.add("practice"); 
        mylist1.add("code"); 
        mylist1.add("quiz"); 
        mylist1.add("geeksforgeeks"); 
          
        // Let us create vector of strings 
        List<String>  mylist2 = new Vector<String>(); 
        mylist2.add("geeks"); 
        mylist2.add("geek"); 
        mylist2.add("for"); 
        mylist2.add("coder"); 
          
        // Let us create a vector  
        List mylist3 = new Vector(); 
          
        mylist3.add(1);  
        mylist3.add("practice");      
          
        // Let us create a Set of strings 
        Set<String>  mylist4 = new HashSet<String>(); 
        mylist4.add("practice"); 
        mylist4.add("code"); 
        mylist4.add("quiz"); 
        mylist4.add("geeksforgeeks"); 
          
          
        // Here we are using disjoint() method to check  
        // whether two collections are disjoint or not 
        System.out.println("is mylist1 disjoint to mylist2:" + 
                            Collections.disjoint(mylist1, mylist2)); 
          
        System.out.println("is mylist1 disjoint to mylist3:" + 
                            Collections.disjoint(mylist1, mylist3)); 
          
        System.out.println("is mylist1 disjoint to mylist4:" + 
                            Collections.disjoint(mylist1, mylist4)); 
  
    } 
}

輸出：

is mylist1 disjoint to mylist2:true
is mylist1 disjoint to mylist3:false
is mylist1 disjoint to mylist4:false

How to quickly check whether two arrays in Java are disjoint or not?

Java中的Arrays類沒有脫節方法。我們可以使用Collections.disjoint()快速檢查兩個數組的不相交性。

// Java program to demonstrate disjoint  
// method with arrays 
  
import java.util.*; 
   
public class DisjointDemo 
{ 
    public static void main(String[] args) 
    { 
        // Let us create  arrays of integers 
        Integer arr1[] = {10, 20, 30, 40, 50}; 
        Integer arr2[] = {60, 70, 80, 90, 100}; 
        Integer arr3[] = {50, 70, 80, 90, 100}; 
        Double  arr4[] = {50.0, 60.0, 110.0}; 
          
          
        // Please refer below post for details of asList() 
        // https://www.geeksforgeeks.org/array-class-in-java/ 
        // Here we are using disjoint() method to check  
        // whether two arrays are disjoint or not 
        System.out.println("is arr1 disjoint to arr2:" + 
                         Collections.disjoint(Arrays.asList(arr1), Arrays.asList(arr2))); 
          
        System.out.println("is arr1 disjoint to arr3:" + 
                         Collections.disjoint(Arrays.asList(arr1), Arrays.asList(arr3))); 
          
        System.out.println("is arr1 disjoint to arr4:" + 
                         Collections.disjoint(Arrays.asList(arr1), Arrays.asList(arr4))); 
  
    } 
}

輸出：

is arr1 disjoint to arr2:true
is arr1 disjoint to arr3:false
is arr1 disjoint to arr4:true

相關用法

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