import ballerina/io;
import ballerina/regex;

public function main() {

    // Checks whether the given string matches the provided regex.
    // You need to provide the original `string` and the regex to
    // this string, which is to be matched with.
    boolean isMatched = regex:matches("This Should Match", "Th.*ch");
    io:println("Is the given string matched with the original string: ",
                isMatched);

    // Replaces each occurrence of the substrings, which match the provided
    // regular expression from the given original string value with the
    // provided replacement string.
    string new_string = regex:replaceAll("Ballerina is great", "\\s+", "_");
    io:println("Replaced string: ", new_string);

    // Replaces the first substring that matches the given regular expression
    // with the provided `replacement` string.
    new_string = regex:replaceFirst("ReplacethisthisTextThis", "this", " ");
    io:println("String after replacing first Match: ", new_string);

    // Retrieves an array of strings by splitting a string using the provided
    // delimiter.
    string[] names = regex:split("amal, kamal, nimal, sunimal", ",");
    io:println("No of names: ", names.length());
}

Regular Expressions

The regex library provides functionalities for searching, splitting, and replacing the set of characters of the string by using the regular expression.

For more information on the underlying module, see the Regex module.

import ballerina/io;
import ballerina/regex;
public function main() {
    boolean isMatched = regex:matches("This Should Match", "Th.*ch");
    io:println("Is the given string matched with the original string: ",
                isMatched);

Checks whether the given string matches the provided regex. You need to provide the original string and the regex to this string, which is to be matched with.

    string new_string = regex:replaceAll("Ballerina is great", "\\s+", "_");
    io:println("Replaced string: ", new_string);

Replaces each occurrence of the substrings, which match the provided regular expression from the given original string value with the provided replacement string.

    new_string = regex:replaceFirst("ReplacethisthisTextThis", "this", " ");
    io:println("String after replacing first Match: ", new_string);

Replaces the first substring that matches the given regular expression with the provided replacement string.

    string[] names = regex:split("amal, kamal, nimal, sunimal", ",");
    io:println("No of names: ", names.length());
}

Retrieves an array of strings by splitting a string using the provided delimiter.

bal run regex_expressions.bal
Is the given string matched with the original string: true
Replaced string: Ballerina_is_great
String after replacing first Match: Replace thisTextThis
No of names: 4