Get all digits from a string

With this example we are going to demonstrate how to get all digits from a String, using a regular expression. In short, to get all digits from a String you should:

  • Use a given String with letters and digits.
  • Use replaceAll(String regex, String replacement) API method of String, with a given regular expression and a String to be used as replacement. The regular expression is constructed by a digit and the replacement String is an empty String. The method replaces each substring of this string that matches the given regular expression with the given replacement. An invocation of this method of the form str.replaceAll(regex, repl) yields exactly the same result as the expression java.util.regex.Pattern.compile(regex).matcher(str).replaceAll(repl).

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

public class Main {
  public static void main(String[] argv) throws Exception {

    System.out.println("abasdfasdf1 2wasdfasdf9_8asdfasdfz asdfasdfyx7".replaceAll("\\D", ""));




This was an example of how to get all digits from a String in Java.

Byron Kiourtzoglou

Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.
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