In this post, we will learn “How to find Max & Min from a List using Java 8 Streams API?”.
Here, we are going to learn following things:
- How to Find Max & Min Number in a List?
- How to Find Max & Min String in a List?
- How to Find Max & Min Object by Key in a List?
Find Max or Min from a List using Java 8 Streams...!!! Click To Tweet
Let’s Begin,
1. Find Max & Min Number in a List
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | import java.util.Arrays; import java.util.Comparator; import java.util.List; import java.util.NoSuchElementException; import java.util.OptionalInt; public class Find_Max_Min_Integer_ArrayList_Java8 { public static void main(String[] args) { List <Integer> list = Arrays.asList(40, 32, 53, 22, 11, 89, 76); //1st way of finding maximum value OptionalInt maxNumber1 = list.stream() .mapToInt(value -> value) .max(); System.out.println("Maximum Value Element in the List: " + maxNumber1); //2nd way of finding maximum value int maxNumber2 = list.stream() .mapToInt(value -> value) .max() .orElseThrow(NoSuchElementException::new); System.out.println("Maximum Value Element in the List: " + maxNumber2); //3rd way of finding maximum value int maxNumber3 = list.stream() .max(Comparator.comparing(Integer::valueOf)) .get(); System.out.println("Maximum Value Element in the List: " + maxNumber3); //1st way of finding minimum value OptionalInt minNumber1 = list.stream() .mapToInt(value -> value) .min(); System.out.println("Minimum Value Element in the List: " + minNumber1); //2nd way of finding minimum value int minNumber2 = list.stream() .mapToInt(value -> value) .min() .orElseThrow(NoSuchElementException::new); System.out.println("Minimum Value Element in the List: " + minNumber2); //3rd way of finding minimum value int minNumber3 = list.stream() .min(Comparator.comparing(Integer::valueOf)) .get(); System.out.println("Minimum Value Element in the List: " + minNumber3); } } |
Output:
1 2 3 4 5 6 | Maximum Value Element in the List: OptionalInt[89] Maximum Value Element in the List: 89 Maximum Value Element in the List: 89 Minimum Value Element in the List: OptionalInt[11] Minimum Value Element in the List: 11 Minimum Value Element in the List: 11 |
2. Find Max & Min String in a List
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 | import java.util.Arrays; import java.util.Comparator; import java.util.List; import java.util.NoSuchElementException; import java.util.Optional; public class Find_Max_Min_String_ArrayList_Java8 { public static void main(String[] args) { List <String> list = Arrays.asList("Tom", "Henry", "Adam", "Sandy", "Ross"); //1st way of finding maximum char Optional <String> maxChar1 = list.stream() .max(Comparator.comparing(String::valueOf)); System.out.println("Maximum Character Element in the List: " + maxChar1); //2nd way of finding maximum char String maxChar2 = list.stream() .max(Comparator.comparing(String::valueOf)) .orElseThrow(NoSuchElementException::new); System.out.println("Maximum Character Element in the List: " + maxChar2); //1st way of finding minimum char Optional <String> minChar1 = list.stream() .min(Comparator.comparing(String::valueOf)); System.out.println("Minimum Character Element in the List: " + minChar1); //2nd way of finding maximum char String minChar2 = list.stream() .min(Comparator.comparing(String::valueOf)) .orElseThrow(NoSuchElementException::new); System.out.println("Minimum Character Element in the List: " + minChar2); } } |
Output:
1 2 3 4 | Maximum Character Element in the List: Optional[Tom] Maximum Character Element in the List: Tom Minimum Character Element in the List: Optional[Adam] Minimum Character Element in the List: Adam |
3. Find Max & Min Object by Key in a List
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | import java.util.Arrays; import java.util.Comparator; import java.util.List; public class Find_Max_Min_Object_By_Key_ArrayList_Java8 { public static void main(String[] args) { List < Person > persons = Arrays.asList( new Person("Tom", 3), new Person("Sam", 5), new Person("Andy", 12), new Person("Jazz", 18), new Person("Brett", 9) ); //Get Max age Person info Person maxPerson = persons.stream() .max(Comparator.comparing(Person::getAge)) .get(); System.out.printf("%s has the maximum age among the list which is %s", maxPerson.getName(), maxPerson.getAge()); System.out.println("\n"); //Get Min age Person info Person minPerson = persons.stream() .min(Comparator.comparing(Person::getAge)) .get(); System.out.printf("%s has the minimum age among the list which is %s", minPerson.getName(), minPerson.getAge()); } } |
Person (POJO class):
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | public class Person { private String name; private int age; public Person(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } } |
Output:
1 2 3 | Jazz has the maximum age among the list which is 18 Tom has the minimum age among the list which is 3 |
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