Count a group of words

Count All Words

For this use case first I take one String variable with a value I take below the String value you can take another String value you want. After that we need to count a group of words means the group can contain certain boundaries like the starting position of a group of words and the ending position of a group of words. To count words in the group, we need to create a regex pattern for this logic.

Required Pattern

"\\b" + startingBoundary + "\\b\\s*(.*?)\\s*\\b" + endingBoundary + "\\b"

Explanation of Pattern:

\\b represents the boundary value in regex pattern
This startingBoundary variable represents the starting value of group
\s this represents the white spaces in the String value
(.*?) It can represents the capturing group for any characters in given String
After that again I set the ending boundary value by using endingBoundary variable

Java Program to Count group of words

Java

// Java Program to Extract Words Between Boundaries 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
  
// Driver Class 
public class WordsBetweenBoundariesExample { 
      // Main function 
    public static void main(String[] args) { 
  
        // Input string 
        String inputString = "Welcome to w3wiki Best Online Platform for"
          + " learning Computer Science Subjects"; 
  
        // Starting and ending boundaries 
        String startingBoundary = "Best"; 
        String endingBoundary = "Subjects"; 
  
        // Regular expression to capture words between boundaries 
        String wordRegex = "\\b" + startingBoundary + "\\b\\s*(.*?)\\s*\\b" + endingBoundary + "\\b"; 
  
        // Create a Pattern object 
        Pattern pattern = Pattern.compile(wordRegex, Pattern.CASE_INSENSITIVE | Pattern.DOTALL); 
  
        // Create a Matcher object 
        Matcher matcher = pattern.matcher(inputString); 
  
        // Find the words between boundaries 
        if (matcher.find()) { 
            // Group 1 contains the words between boundaries 
            String wordsBetweenBoundaries = matcher.group(1); 
  
            // Split the captured words to count the number of words 
            String[] wordsArray = wordsBetweenBoundaries.split("\\s+"); 
            int wordCount = wordsArray.length; 
  
            // Display the input string 
            System.out.println("\n\tInput string: " + inputString); 
            System.out.println("\n\tStarting boundary Value: " + startingBoundary); 
            System.out.println("\n\tEnding boundary Value: " + endingBoundary); 
  
            // Display the result 
            System.out.println("\n\tNumber of words between boundaries: " + wordCount); 
            System.out.println("\n\tWords between boundaries: "); 
            for (String word : wordsArray) 
                System.out.print("\n\t" + word + ", "); 
        }  
            
          else { 
            // Display the input string 
            System.out.println("\n\tInput string: " + inputString); 
            System.out.println("\n\tStarting boundary Value: " + startingBoundary); 
            System.out.println("\n\tEnding boundary Value: " + endingBoundary); 
  
            // No match found 
            System.out.println("\n\tNo match found between boundaries."); 
        } 
    } 
} 

Output

Output while No match found between boundaries

Explaination of the above Program:

In this above code first I import the required packages with required classes those Pattern and Matcher. After That I take One Sting value. After that I choose starting and ending boundary values from given string and assign them to two variables namely startingBoundary and endingBoundary. Now I will apply the regex pattern as per out requirement. After apply the regex we get some result. This result is stored in String type array. After that I used Pattern and Matcher classes for Matching the required pattern using Matcher class, then I count the size of that words using that array. Finally I print the result using print statement. If no words are found between given boundaries then we got message like No match found between boundaries. I will provide output images in the below for better understanding the concept with java code.