Extract Digits from a String in Java using regular expression

In this post we show you how to use regular expressions to remove all non-digits characters of a String and return the number only String in Java application.

Following Java example code use String.replaceAll() method with regex “[^0-9]” to replace non-digits characters in a String with empty String.

public class ExtractDigitsFromStringExample1 {

    public static void main(String[] args) {
        String testString = "Java was released in 1995";
        String numberOnlyString = testString.replaceAll("[^0-9]", "");

        System.out.println(numberOnlyString);
    }

}

Output:

Java example code below using regex “\D+” which returns the same result.

public class ExtractDigitsFromStringExample2 {

    public static void main(String[] args) {
        String testString = "My phone number is 123-456-789";
        String numberOnlyString = testString.replaceAll("\\D+", "");

        System.out.println(numberOnlyString);
    }

}

Output:

123456789

Java code example that use java.util.regex.Pattern with regex “[^0-9]”

import java.util.regex.Pattern;

public class ExtractDigitsFromStringExample3 {

    public static void main(String[] args) {
        String testString = "The price of this product is $123";
        Pattern notDigitsPattern = Pattern.compile("[^0-9]");
        String numberOnlyString = notDigitsPattern.matcher(testString).replaceAll("");

        System.out.println(numberOnlyString);
    }

}

Output:

Java code example that use java.util.regex.Pattern with regex “\D+”

import java.util.regex.Pattern;

public class ExtractDigitsFromStringExample4 {

    public static void main(String[] args) {
        String testString = "Your OTP (one time password) is 485743";
        Pattern notDigitsPattern = Pattern.compile("\\D+");
        String numberOnlyString = notDigitsPattern.matcher(testString).replaceAll("");

        System.out.println(numberOnlyString);
    }
}

Output:

Happy Coding 😊