Delete part of a string question

Question

Hello I have this String 12a
I need to get a the value 12 of it an make it an int
But the problem is that I don't know what the string is it can be
12
or 12 a
or 12a
It is for people to fill in there house address and this is the number part.
The string is like this String number ="\"12a\"";
Is it possible to look for a letter in a String and delete it if you only want ints???

Answer 1

Try this on the command line. Dealing with java.lang.NumberFormatException in cases where the number is too large is left as an exercise.
Harald.
import java.util.regex.*;
* demonstrates use of <code>java.util.regex</code> to check if a
* string starts with digits.
public class bla {
   * thrown by {@link #getNumber} if the given string does not start
   * with digits.
  private static class BoomBoom extends Exception {
    public BoomBoom(String msg) {super(msg);}
   * reusable pattern to check for digits.
  private static Pattern p = Pattern.compile("[0-9]+");
   * convert leading digits of the parameter to an <code>int</code>
   * and return it.
   * @throws BoomBoom if the parameter does not start with digits.
  public static int getNumber(String s) throws BoomBoom {
    Matcher m = p.matcher(s);
    if( !m.lookingAt() ) {
      throw new BoomBoom("The string `"+s+"' does not start with "
                +"a positive number.");
    return Integer.parseInt(m.group(0));
  // don't clutter the javadoc
  private bla() {}
   * passes each command line argument through {@link #getNumber} and
   * prints the output or error to <code>System.out</code> or
   * <code>System.err</code> respectively.
  public static void main(String[] argv) {
    for(int i=0; i<argv.length; i++) {
      try {
     System.out.println("Your string `"+argv[i]
                  +"' starts with number "
                  +getNumber(argv));
} catch( BoomBoom e ) {
     System.err.println(e.getMessage());