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Java 8 - filter list using streams (ArrayList)

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Created by:

Tomeriko

413

In this article, we would like to show you how to filter ArrayList in Java.

Quick solution:

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// string filter
 List<String> filtered = myArrayList.stream()
         .filter(string -> string.contains("substring"))
         .collect(Collectors.toList());
​
// integer filter
List<Integer> filtered = myArrayList.stream()
        .filter(number -> number > 2)
        .collect(Collectors.toList());

Practical examples

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Example 1

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In this example, we check if elements from fruits ArrayList contain specified substring and save the elements that does in a new filtered ArrayList.

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import java.util.*;
import java.util.stream.Collectors;
​
public class Example {
​
    public static void main(String[] args) {
        List<String> fruits = new ArrayList<>();
​
        fruits.add("apple");
        fruits.add("banana");
        fruits.add("cherry");
        fruits.add("grapes");
​
        List<String> filtered = fruits.stream()
                .filter(string -> string.contains("ap"))
                .collect(Collectors.toList());
​
        System.out.println(filtered);
    }
}

Output:

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[apple, grapes]

Example 2

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In this example, we check if elements from numbers ArrayList satisfy the specified condition and save the elements that does in a new filtered ArrayList.

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import java.util.*;
import java.util.stream.Collectors;
​
public class Example {
​
    public static void main(String[] args) {
        List<Integer> numbers = new ArrayList<>();
​
        numbers.add(1);
        numbers.add(2);
        numbers.add(3);
        numbers.add(4);
​
        List<Integer> filtered = numbers.stream()
                .filter(number -> number > 2)
                .collect(Collectors.toList());
​
        System.out.println(filtered);
    }
}