How to extract numbers from a string using regular expressions?

You can match numbers in the given string using either of the following regular expressions −

“\d+”
Or,
"([0-9]+)"

Example 1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class ExtractingDigits {
   public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter sample text: ");
      String data = sc.nextLine();
      //Regular expression to match digits in a string
      String regex = "\d+";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Creating a Matcher object
      Matcher matcher = pattern.matcher(data);
      System.out.println("Digits in the given string are: ");
      while(matcher.find()) {
         System.out.print(matcher.group()+" ");
      }
   }
}

Output

Enter sample text:
this is a sample 23 text 46 with 11223 numbers in it
Digits in the given string are:
23 46 11223

Example 2

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Just {
   public static void main(String[] args) {
      String data = "abc12def334hjdsk7438dbds3y388";
      //Regular expression to digits
      String regex = "([0-9]+)";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      //Creating a Matcher object
      Matcher matcher = pattern.matcher(data);
      System.out.println("Digits in the given string are: ");
      while(matcher.find()) {
         System.out.print(matcher.group()+" ");
      }
   }
}

Output

Digits in the given string are:
12 334 7438 3 388