Pattern quote(String) method in Java with Examples

quote(String) method of a Pattern class used to returns a literal pattern String for the specified String passed as parameter to method.This method produces a String equivalent to s that can be used to create a Pattern. Metacharacters or escape sequences in the input sequence will be given no special meaning. If you compile the value returned by the quote method, you’ll get a Pattern which matches the literal string that you passed as a parameter to method.\Q and \E mark the beginning and end of the quoted part of the string. Syntax:

public static String quote(String s)

Parameters: This method accepts a single parameter s which represents the string to be literalized. Return value: This method returns a literal string replacement for String s. Below programs illustrate the quote() method: Program 1:

Java

// Java program to demonstrate
// Pattern.quote() method

import java.util.regex.*;

public class GFG {
    public static void main(String[] args)
    {
        // create a REGEX String
        String REGEX = "ee";

        // create the string
        // in which you want to search
        String actualString
            = "geeksforgeeks";

        // create equivalent String for REGEX
        String eqREGEX = Pattern.quote(REGEX);

        // create a Pattern using eqREGEX
        Pattern pattern = Pattern.compile(eqREGEX);

        // get a matcher object
        Matcher matcher = pattern.matcher(actualString);

        // print values if match found
        boolean matchfound = false;
        while (matcher.find()) {
            System.out.println("found the Regex in text:"
                               + matcher.group()
                               + " starting index:"
                               + matcher.start()
                               + " and ending index:"
                               + matcher.end());

            matchfound = true;
        }
        if (!matchfound) {
            System.out.println("No match found for Regex.");
        }
    }
}

Output:

found the Regex in text:ee starting index:1 and ending index:3
found the Regex in text:ee starting index:9 and ending index:11

Time Complexity : O(n)

Space Complexity : O(1)

Program 2:

Java

// Java program to demonstrate
// Pattern.quote() method

import java.util.regex.*;

public class GFG {
    public static void main(String[] args)
    {
        // create a REGEX String
        String REGEX = "welcome";

        // create the string
        // in which you want to search
        String actualString
            = "welcome to jungle";

        // create equivalent String for REGEX
        String eqREGEX = Pattern.quote(REGEX);

        // create a Pattern using eqREGEX
        Pattern pattern = Pattern.compile(eqREGEX);

        // get a matcher object
        Matcher matcher = pattern.matcher(actualString);

        // print values if match found
        boolean matchfound = false;
        while (matcher.find()) {
            System.out.println("match found");
            matchfound = true;
        }
        if (!matchfound) {
            System.out.println("No match found");
        }
    }
}

Output:

match found

Time Complexity : O(n)

Space Complexity : O(1)

Reference: https://docs.oracle.com/javase/10/docs/api/java/util/regex/Pattern.html#quote(java.lang.String)