How to test if a List contains a specific value in Java
[CG]BOUGA
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// {
import java.util.Arrays;
import java.util.List;
class User {
public int id;
public String name;
User(int id, String name) {
this.id = id;
this.name = name;
}
public String toString() {
return "{ id: " + id + ", name: " + name + " }";
}
}
public class Main {
public static List<User> getUsers() {
return Arrays.asList(
new User(1, "Ali"),
new User(2, "Bobby"),
new User(3, "Charlie"),
new User(4, "Dora")
);
}
public static void main(String[] args) throws Exception {
// }
// Method 1: basic structures
List<Integer> integers = Arrays.asList(1, 2, 3, 4, 5);
int integerToFind = 6;
boolean integerExists = integers.contains(integerToFind);
System.out.println("6 is the list: " + integerExists);
// Method 2: complex structures
List<User> users = getUsers();
String userToFind = "Bobby";
boolean userExists = users.stream().anyMatch(user -> userToFind.equals(user.name));
System.out.println("Bobby is in the list: " + userExists);
// Method 3: find the element that matches the condition
User bobby = users.stream()
.filter(user -> userToFind.equals(user.name))
.findFirst()
.orElse(null);
System.out.println("Bobby: " + bobby);
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