Java 8 – Count and print number of repeated word occurrences in a text file

In this article, we will count and print number of repeated word occurrences in a text file i.e.;

Counting & Printing duplicate word occurrences:

  • Using Java 8 Stream and java.util.AbstractMap.SimpleEntry
  • Using Java 8 Stream and Collectors.toMap() method
  • Using Pattern.compile(“\W+”).splitAsStream() method

Sample text file:

1. Using Java 8 Stream and SimpleEntry

CountRepeatedWordsUsingJava8.java

package in.bench.resources.count.lines.words;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.AbstractMap.SimpleEntry;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Map;
import java.util.stream.Collectors;

public class CountRepeatedWordsUsingJava8 {

	public static void main(String[] args) throws IOException {

		// read file from root folder
		Path path = Paths.get("Words.txt"); // get file location


		// count repeated words
		Map<String, Long> wordCountMap = Files.lines(path) // read all lines in file
				.parallel() // parallely
				.flatMap(line -> Arrays.stream(line.trim().split(" "))) // split words on space
				.map(word -> word.replaceAll("[^a-zA-Z]", "").trim()) // remove white-spaces
				.filter(word -> word.length() > 0) // filter word length greater than 1
				.map(word -> new SimpleEntry<>(word, 1)) // put it in temp Entry
				.collect(Collectors.groupingBy(SimpleEntry::getKey, Collectors.counting()));


		// print to the console
		System.out.println("1. Words and its Count in Random-order :- \n");
		wordCountMap
		.entrySet()
		.forEach(System.out::println);


		// print to the console
		System.out.println("\n\n2. Words and its Count in Descending-order :- \n");
		wordCountMap
		.entrySet()
		.stream()
		.sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
		.forEach(System.out::println);
	}
}

Output:

1. Words and its Count in Random-order :- 

Social=1
Telugu=1
English=2
Maths=2
blank=15
Kannda=1
Science=1
Hindi=2
Civics=2
History=1
Tamil=3
Physics=1


2. Words and its Count in Descending-order :- 

blank=15
Tamil=3
English=2
Maths=2
Hindi=2
Civics=2
Social=1
Telugu=1
Kannda=1
Science=1
History=1
Physics=1

2. Using Java 8 Stream and Collectors.toMap() method

CountRepeatedWordsUsingJava8CollectorsToMap.java

package in.bench.resources.count.lines.words;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;

public class CountRepeatedWordsUsingJava8CollectorsToMap {

	public static void main(String[] args) throws IOException {

		// read file from root folder
		Path path = Paths.get("Words.txt"); // get file location


		// count repeated words
		Map<String, Long> wordCountMap = Files.lines(path) // read all lines in file
				.parallel() // parallely
				.flatMap(line -> Arrays.stream(line.trim().split(" "))) // split words on space
				.map(word -> word.replaceAll("[^a-zA-Z]", "").trim()) // remove white-spaces
				.filter(word -> !word.isEmpty()) // filter words which isn't empty
				.collect(Collectors.groupingBy(Function.identity(), Collectors.counting()));


		// print to the console
		System.out.println("1. Words and its Count in Random-order :- \n");
		wordCountMap
		.entrySet()
		.forEach(System.out::println);


		// print to the console
		System.out.println("\n\n2. Words and its Count in Ascending-order :- \n");
		wordCountMap
		.entrySet()
		.stream()
		.sorted(Map.Entry.comparingByValue())
		.forEach(System.out::println);
	}
}

Output:

1. Words and its Count in Random-order :- 

Social=1
Telugu=1
English=2
Maths=2
blank=15
Kannda=1
Science=1
Hindi=2
Civics=2
History=1
Tamil=3
Physics=1


2. Words and its Count in Ascending-order :- 

Social=1
Telugu=1
Kannda=1
Science=1
History=1
Physics=1
English=2
Maths=2
Hindi=2
Civics=2
Tamil=3
blank=15

3. Using Pattern.compile().splitAsStream() method

  • First, read file lines parallelly using Files.readAllLines() and convert to String using toString() method
  • Form a regex expression to split each word from a text file using Pattern.compile(“\\W+”) and at the same time convert it into Stream using splitAsStream() method passing string read from file as argument
  • Filter out word which isn’t empty using Stream.filter() method
  • Finally, collect words and its count using Java 8 Collectors after converting words into lowercase

CountRepeatedWordsUsingJava8PatternSplitAsStream.java

package in.bench.resources.count.lines.words;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Comparator;
import java.util.Map;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

public class CountRepeatedWordsUsingJava8PatternSplitAsStream {

	public static void main(String[] args) throws IOException {

		// read file from root folder
		Path path = Paths.get("Words.txt"); // get file location


		// read all lines and convert to String to process
		String input = Files.readAllLines(path).toString();


		// count repeated words, ignoring case
		Map<String, Integer> wordCountMap = Pattern.compile("\\W+")
				.splitAsStream(input)
				.filter(word -> !word.isEmpty()) // filter words which isn't empty
				.collect(Collectors.groupingBy(String::toLowerCase,
						Collectors.summingInt(s -> 1))); // calculate repeated count


		// print to the console
		System.out.println("1. Words and its Count in Random-order :- \n");
		wordCountMap
		.entrySet()
		.forEach(System.out::println);


		// print to the console
		System.out.println("\n\n2. Words and its Count in Descending-order :- \n");
		wordCountMap
		.entrySet()
		.stream()
		.sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
		.forEach(System.out::println);
	}
}

Output:

1. Words and its Count in Random-order :- 

kannda=1
tamil=3
blank=15
social=1
maths=2
civics=2
physics=1
science=1
hindi=2
english=2
history=1
telugu=1


2. Words and its Count in Descending-order :- 

blank=15
tamil=3
maths=2
civics=2
hindi=2
english=2
kannda=1
social=1
physics=1
science=1
history=1
telugu=1

Related Articles:

References:

Happy Coding !!
Happy Learning !!

Java 8 – Count and print number of repeated character occurrences in a String
Java 8 – Count and print number of lines and words in a text file