How to Filter Items of a Set based on a Condition in Java - Step by Step Examples

How to Filter Items of a Set based on a Condition in Java ?

Answer

To filter items of a set based on a condition in Java, you can iterate through the set and selectively add items that satisfy the condition to a new set.


✐ Examples

1 Filter Even Numbers from a Set

In this example,

  1. First, we create a set of integers named numberSet with values {1, 2, 3, 4, 5, 6}.
  2. Next, we create a new set called evenNumbers.
  3. We iterate through each element of numberSet using a for-each loop.
  4. Within the loop, we check if the current number is even using the modulo operator %.
  5. If the number is even, we add it to the evenNumbers set.

Java Program

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Set<Integer> numberSet = new HashSet<>(Arrays.asList(1, 2, 3, 4, 5, 6));
        Set<Integer> evenNumbers = new HashSet<>();
        for (int num : numberSet) {
            if (num % 2 == 0) {
                evenNumbers.add(num);
            }
        }
        System.out.println("Even numbers: " + evenNumbers);
    }
}

Output

Even numbers: [2, 4, 6]

2 Filter Strings Starting with 'A' from a Set

In this example,

  1. First, we create a set of strings named stringSet with values {"Apple", "Banana", "Apricot", "Orange"}.
  2. Next, we create a new set called filteredStrings.
  3. We iterate through each element of stringSet using a for-each loop.
  4. Within the loop, we check if the current string starts with 'A' using the startsWith() method.
  5. If the string starts with 'A', we add it to the filteredStrings set.

Java Program

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Set<String> stringSet = new HashSet<>(Arrays.asList("Apple", "Banana", "Apricot", "Orange"));
        Set<String> filteredStrings = new HashSet<>();
        for (String str : stringSet) {
            if (str.startsWith("A")) {
                filteredStrings.add(str);
            }
        }
        System.out.println("Strings starting with 'A': " + filteredStrings);
    }
}

Output

Strings starting with 'A': [Apricot, Apple]

Summary

In this tutorial, we learned How to Filter Items of a Set based on a Condition in Java language with well detailed examples.


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