Question

How to check and extract a number from a String in Java

Answer 1

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MyClass {
    public static String extractNumberFromString(String s) {
        Pattern pt = Pattern.compile("\\d+");
        Matcher mt = pt.matcher(s);
        
        if (mt.find()) {
            return mt.group();
        } else {
            return "not found";
        }
    }
    public static void main(String args[]) {
        String s = "Java 21 is a high-level, class-based, object-oriented programming language";

        String number = extractNumberFromString(s);
        
        System.out.println(number);
    }
}
 
  
  
  
/*
run:
       
21
    
*/

 

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