Java set operations -- intersection and union of two sets

Java calculates the intersection and union of two sets

How does Java calculate the intersection and union of two sets ?? In fact, Java APIs have encapsulated methods. Today, I will write a simple example to test it: (Java. util. Collections list is used as an example)

Calculate the intersection of connected sets:

Import Java. util. arraylist; import Java. util. list; public class testcollection {public static void main (string [] ARGs) {list <string> strlist = new arraylist <string> (); list <string> strlist2 = new arraylist <string> (); For (INT I = 0; I <10; I ++) {strlist. add ("AAA>" + I); strlist2.add ("AAA>" + (10-I);} // obtain the intersection strlist2.retainall (strlist); system. out. println ("intersection size:" + strlist2.size (); For (INT I = 0; I <strlist2.size (); I ++) {system. out. println (strlist2.get (I ));}}}

　　

Calculate the union of the two sets:

Import Java. util. arraylist; import Java. util. list; public class testcollection {public static void main (string [] ARGs) {list <string> strlist = new arraylist <string> (); list <string> strlist2 = new arraylist <string> (); For (INT I = 0; I <10; I ++) {strlist. add ("AAA>" + I); strlist2.add ("AAA>" + (10-I);} // obtain the Union strlist2.removeall (strlist ); strlist2.addall (strlist); system. out. println ("Union set size:" + strlist2.size (); For (INT I = 0; I <strlist2.size (); I ++) {system. out. println (strlist2.get (I ));}}}

The example is very simple and I hope it will help you !!!