Counting word occurence with arrays stream in Java 8

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How I can calculate word frequency in a string with using arrays stream? I'm using Java 8.

Here is my code:

String sentence = "The cat has black fur and black eyes";
String[] bites = sentence.trim().split("\\s+");

String in = "black cat";

calculate words "black" and "cat" frequency in the sentence. Word "black" frequency is 2 and word "cat" is 1.

So the goal output is then 3.

    String sentence = "The cat has black fur and black eyes";
    String[] bites = sentence.trim().split("\\s+");
    String in = "black cat";
    long i = Stream.of(bites).filter(e->(Arrays.asList(in.split("\\s")).contains(e))).count();
    System.out.println(i);

Word Frequency Count in Java 8, In this tutorial you will how to find out word frequency count using Java 8 Stream api. Arrays;; import java.util.List;; import java.util.Map;; import  In Java 8, we can convert the given set of words to stream and use a collector to count the occurrences of elements in a Stream. The groupingBy (classifier, downstream) collector converts the collection of elements into a Map by grouping elements according to a classification function,

How about

Map<String, Long> counts = yourStringStream
    .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

This gives you a Map from all words to their frequency count.

Efficient Word Frequency Calculator in Java, Explore various ways of counting words in Java and see how they perform. Let's start by simply calculating the word count of words in this array: ? Now, let's leverage Java 8 Stream API, parallel Streams, and the  This quick code tip shows how to count number of words in a text file in Java 8 using the Streams API along with the NIO API. Do take a note of how the file contents are read and the words counted using a single line of pipelined instructions with the Java 8 Streams API.

Map<String, Long> count = Arrays.stream(bites)
        .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

Create a Frequency Map in Java 8 and above, In Java 8, we can convert the given set of words to stream and use a collector to count the occurrences of elements in a Stream. The groupingBy(classifier  Following code snippet shows how you can write a word count program using Java 8 Stream API. The better solution is using toMap collector as shown below. Even better version can be written using grouping and counting collector as shown below.

String sentence = "The cat has black fur and black eyes";
String[] bites = sentence.trim().split("\\s+");

Map<String, Long> counts = Arrays.stream(bites)
       .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));

Word count example in Java 8 – Shekhar Gulati, code snippet shows how you can write a word count program using Java 8 Stream API. flatMap(line -> Arrays.stream(line.trim().split( "s" ))). Stream count() method in Java with examples. long count() returns the count of elements in the stream. This is a special case of a reduction (A reduction operation takes a sequence of input elements and combines them into a single summary result by repeated application of a combining operation).

Although many examples showing how it's been done with streams are great. You still shouldn't forget that Collections already has a method that does this for you:

List<String> list = Array.asList(bites);
System.out.println(Collections.frequency(list, "black")); // prints 2
System.out.println(Collections.frequency(list, "cat"));   // prints 1

Java stream count number of elements example, Java stream count elements example. To count the number of elements in stream in Java 8, use either the Stream.count() or Collectors.counting() methods. On this page we will provide the examples of concat, count, sorted and distinct stream API methods of java 8. concat method is static and count, sorted and distinct methods are called on stream object created by stream() method calling on collection. Stream.concat concat() is a static method in stream API. It concats two stream object and returns resulting stream object.

Java 8, Arrays.stream() method then creates a Stream of Strings, or Stream<String> for every line. We now effectively have a  Here is different ways of java 8 stream group by count with examples like grouping, counting, filtering, summing, averaging, multi-level grouping. Example 1: Grouping by + Counting. Collectors class provide static factory method groupingBywhich provides a similar kind of functionality as SQL group by clause.

Java 8 stream word count example – StaticReference, In this tutorial, you will learn about java 8 stream word count example. a simple Java 8 stream program to identify the number of word occurrences in String to byte array,byte array to String in Scala 1,839 views | posted on  Java 8. Using a java 8 we will convert the list to a stream then call Stream.filter, an intermediate operation, passing in a lambda expression to exclude all elements that don't match "Elephants". Finally calling a the reduction count method will returns the count of elements.

How to Calculate word frequency using JAVA 8, In this article, I will show how Calculate word frequency of a given list of strings using JAVA 8. This is helpful while return Stream<String[]> .flatMap(Arrays::​stream) Collectors.counting())); // map word strings to. // count. Combine advanced operations of the Stream API to express rich data processing queries. Luckily there’s a solution to this problem using the method flatMap. Let’s see step-by-step how to get to the right solution. First, we need a stream of words instead of a stream of arrays. There’s a method

Comments
  • Pattern.compile("\\b(black|cat)\\b").splitAsStream(sentence).count()-1
  • @Holger: Nice! But must pad sentence with a dummy word because it does not work when the last word is cat.
  • @YCF_L thanks for the hint. Edited my answer, changed from String.contains to List.contains.
  • It’s a waste of resources to repeat the Arrays.asList(in.split("\\s")) operation for every word.
  • This is not the correct answer as it doesn't compute separate counting...
  • the collecting part can be completly omitted. You just could filter and then use count() to get the exact same result
  • Completely missed it, the final aggregate result doesn't need any grouping (ty btw).
  • You might aswell want to save the list (Arrays.asList()) once and not always create a new throw away object in the stream