「Java」Collectionsのreverseメソットでリストの要素を逆にするサンプル

説明
reverse(List<?> list)
指定されたリストの要素の順序を逆にします。
Javaコード

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package com.arkgame.java.study;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
public class CollectionRerveDemo {
public static void main(String[] args) {
String[] uuArr = { "A001", "B002", "C003", "D004" };
List<String> cftLst = new ArrayList<String>();
cftLst = Arrays.asList(uuArr);
System.out.println("リストの要素(reverse before)");
for (String ss : cftLst) {
System.out.print(ss + "\n");
}
Collections.reverse(cftLst);
System.out.println("リストの要素(reverse after)");
for (String ss : cftLst) {
System.out.print(ss + "\n");
}
}
}
package com.arkgame.java.study; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.List; public class CollectionRerveDemo { public static void main(String[] args) { String[] uuArr = { "A001", "B002", "C003", "D004" }; List<String> cftLst = new ArrayList<String>(); cftLst = Arrays.asList(uuArr); System.out.println("リストの要素(reverse before)"); for (String ss : cftLst) { System.out.print(ss + "\n"); } Collections.reverse(cftLst); System.out.println("リストの要素(reverse after)"); for (String ss : cftLst) { System.out.print(ss + "\n"); } } }
package com.arkgame.java.study;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class CollectionRerveDemo {

      public static void main(String[] args) {

            String[] uuArr = { "A001", "B002", "C003", "D004" };
            List<String> cftLst = new ArrayList<String>();
            cftLst = Arrays.asList(uuArr);
            System.out.println("リストの要素(reverse before)");
            for (String ss : cftLst) {
                  System.out.print(ss + "\n");
            }
            Collections.reverse(cftLst);
            System.out.println("リストの要素(reverse after)");
            for (String ss : cftLst) {
                  System.out.print(ss + "\n");
            }

      }

}

結果
リストの要素(reverse before)
A001
B002
C003
D004
リストの要素(reverse after)
D004
C003
B002
A001

Java

Posted by arkgame