Matching specific word patterns with Java regular expressions

01 Oct 2023

programming

Regular expressions (also known as regex) are powerful tools for pattern matching and string manipulation. They allow you to define patterns that can be matched against text strings, making them extremely useful in tasks such as data validation, text searching, and even text processing.

In this blog post, we will explore how to use Java regular expressions to match specific word patterns. Let’s dive in!

Using the `Pattern` and `Matcher` classes

Java provides the Pattern and Matcher classes in the java.util.regex package for working with regular expressions. The Pattern class represents a compiled regular expression, and the Matcher class is used to match the pattern against input text.

Here is an example of how to use these classes to match a specific word pattern:

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class WordPatternMatcher {

    public static void main(String[] args) {

        String text = "The quick brown fox jumps over the lazy dog";

        // Define the pattern
        String pattern = "\\b\\w{5}\\b"; // Matches 5-letter words

        // Compile the pattern
        Pattern compiledPattern = Pattern.compile(pattern);

        // Create a matcher for the input text
        Matcher matcher = compiledPattern.matcher(text);

        // Match the pattern against the text
        while (matcher.find()) {
            System.out.println("Matched word: " + matcher.group());
        }
    }
}

The regular expression pattern \\b\\w{5}\\b in this example matches words that are exactly 5 characters long. Let’s break down the pattern:

\\b - Matches a word boundary, ensuring that the word is not part of a longer word.
\\w{5} - Matches exactly 5 word characters (letters, digits, or underscores).
\\b - Matches another word boundary.

Running the example

When you run the above code, it will output the following:

Matched word: quick
Matched word: brown
Matched word: jumps
Matched word: dog

As you can see, the pattern matches all 5-letter words in the input text.

Conclusion

Java regular expressions provide a flexible and powerful way to match specific word patterns in text strings. By using the Pattern and Matcher classes, you can easily define and apply regex patterns to solve a wide range of problems.

Remember to experiment with different patterns and explore the full potential of regular expressions in Java!

#programming #java

Using the Pattern and Matcher classes

Running the example

Conclusion

Using the `Pattern` and `Matcher` classes