How to Remove Element from List based on a Condition in Java - Step by Step Examples

How to Remove Element from List based on a Condition in Java ?

Answer

To remove elements from a list based on a condition in Java using `java.util.ArrayList`, you can iterate through the list and remove elements that meet the condition.

✐ Examples

1 Remove Elements Greater Than a Threshold

In this example,

We create an ArrayList named numbers with some elements.
We specify the threshold value.
We iterate through the list using a for loop.
Within the loop, we use an if statement to check if the current element is greater than the threshold.
If the condition is met, we remove the element using the remove method.
Finally, we print the modified list to standard output.

Java Program

import java.util.ArrayList;
import java.util.Iterator;

public class Main {
    public static void main(String[] args) {
        ArrayList<Integer> numbers = new ArrayList<>();
        numbers.add(1);
        numbers.add(2);
        numbers.add(3);
        numbers.add(4);
        numbers.add(5);
        int threshold = 3;
        Iterator<Integer> iterator = numbers.iterator();
        while (iterator.hasNext()) {
            int number = iterator.next();
            if (number > threshold) {
                iterator.remove();
            }
        }
        System.out.println("Modified list after removing elements greater than " + threshold + ": " + numbers);
    }
}

Output

Modified list after removing elements greater than 3: [1, 2, 3]

2 Remove Elements Matching a Predicate

In this example,

We create an ArrayList named names with some elements.
We define a predicate interface Condition with a method test that defines the condition.
We iterate through the list using a for-each loop.
Within the loop, we check if the current element satisfies the condition defined by the predicate.
If the condition is met, we remove the element using the remove method.
Finally, we print the modified list to standard output.

Java Program

import java.util.ArrayList;
import java.util.Iterator;

interface Condition<T> {
    boolean test(T element);
}

public class Main {
    public static void main(String[] args) {
        ArrayList<String> names = new ArrayList<>();
        names.add("John");
        names.add("Alice");
        names.add("Michael");
        names.add("Emma");
        int maxLength = 5;
        Condition<String> isLongName = element -> element.length() > maxLength;
        Iterator<String> iterator = names.iterator();
        while (iterator.hasNext()) {
            String name = iterator.next();
            if (isLongName.test(name)) {
                iterator.remove();
            }
        }
        System.out.println("Modified list after removing long names: " + names);
    }
}

Output

Modified list after removing long names: [John, Alice, Emma]

Summary

In this tutorial, we learned How to Remove Element from List based on a Condition in Java language with well detailed examples.

◀ Previous Next ▶

Java Tutorials

Java How-Tos

How to Remove Element from List based on a Condition in Java - Step by Step Examples

How to Remove Element from List based on a Condition in Java ?

Answer

✐ Examples

1 Remove Elements Greater Than a Threshold

Java Program

Output

2 Remove Elements Matching a Predicate

Java Program

Output

Summary

More Java Lists Tutorials