Count int occurrences with Java8

by

Try:

 Map<Integer, Long> counters = persons.stream()
     .collect(Collectors.groupingBy(p -> p.getBirthday().getMonthValue(), 
         Collectors.counting()));

More Related Contents:

  1. Should Java 8 getters return optional type?
  2. Convert Iterable to Stream using Java 8 JDK
  3. Java 8 Streams: multiple filters vs. complex condition
  4. Java 8 stream reverse order
  5. Partition a Java 8 Stream
  6. Convert from List to CompletableFuture
  7. Lambda ‘special void-compatibility rule’ – statement expression
  8. Instance Method Reference and Lambda Parameters
  9. Why is this java Stream operated upon twice?
  10. Modifying local variable from inside lambda
  11. Java 8 Streams – collect vs reduce
  12. How can I get a List from some class properties with Java 8 Stream?
  13. Why doesn’t java.util.Collection implement the new Stream interface?
  14. Stream Filter of 1 list based on another list
  15. In Java 8, why is the default capacity of ArrayList now zero?
  16. Why are class static methods inherited but not interface static methods?
  17. Why does this java 8 stream operation evaluate to Object instead of List or just List?
  18. Optional vs. null. What is the purpose of Optional in Java 8? [duplicate]
  19. In Stream reduce method, must the identity always be 0 for sum and 1 for multiplication?
  20. How do I access a UI element from another controller class in JavaFX?
  21. Comparator.comparing(…) of a nested field
  22. Using JavaFX in JRE 8, “Access restriction” error
  23. Why Functional Interfaces in Java 8 have one Abstract Method?
  24. Annotating the functional interface of a Lambda Expression
  25. Java Lambda expressions [closed]
  26. Are defaults in JDK 8 a form of multiple inheritance in Java?
  27. How to implement a Java stream?
  28. Why didn’t Stream have a toList() method?
  29. Are Java 8 lambdas compiled as inner classes, methods or something else? [duplicate]
  30. non-interference requirement on Java 8 streams

Leave a Comment