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Java - iterate through a List in reverse order
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In this article, we would like to show you how to iterate through a List in reverse order in Java.
1. Using reversed for loop
In this example, we use reversed for loop to iterate through the letters
ArrayList in reverse order.
import java.util.*;
public class Example {
public static void main(String[] args) {
List<String> letters = new ArrayList<>();
letters.add("A");
letters.add("B");
letters.add("C");
for (int i = letters.size(); i-- > 0; ) {
System.out.println(letters.get(i));
}
}
}
Output:
C
B
A
2. Using ListIterator
In this example, we create listIterator
and iterate through the letters
ArrayList in a while
loop using hasPrevious()
method.
import java.util.*;
public class Example {
public static void main(String[] args) {
List<String> letters = new ArrayList<>();
letters.add("A");
letters.add("B");
letters.add("C");
ListIterator<String> listIterator = letters.listIterator(letters.size());
while (listIterator.hasPrevious()) {
System.out.println(listIterator.previous());
}
}
}
Output:
C
B
A
3. Using Collections.reverse()
In this example, we reverse the letters
ArrayList to iterate it backwards.
import java.util.*;
public class Example {
public static void main(String[] args) {
List<String> letters = new ArrayList<>();
letters.add("A");
letters.add("B");
letters.add("C");
System.out.println("ArrayList before reverse: " + letters);
Collections.reverse(letters);
System.out.println("ArrayList after reverse: " + letters);
// iterate over ArrayList
for (String letter : letters) {
System.out.println(letter);
}
}
}
Output:
ArrayList before reverse: [A, B, C]
ArrayList after reverse: [C, B, A]
C
B
A