Most elegant way to detect if a String is a number?

Question

Is there a better, more elegant (and/or possibly faster) way than

boolean isNumber = false;
try{
   Double.valueOf(myNumber);
   isNumber = true;
} catch (Nu         


        

Answer 1

I prefer using a loop over the Strings's char[] representation and using the Character.isDigit() method. If elegance is desired, I think this is the most readable:

package tias;

public class Main {
  private static final String NUMERIC = "123456789";
  private static final String NOT_NUMERIC = "1L5C";

  public static void main(String[] args) {
    System.out.println(isStringNumeric(NUMERIC));
    System.out.println(isStringNumeric(NOT_NUMERIC));
  }

  private static boolean isStringNumeric(String aString) {
    if (aString == null || aString.length() == 0) {
      return false;
    }
    for (char c : aString.toCharArray() ) {
      if (!Character.isDigit(c)) {
        return false;
      }
    }
    return true;
  }

}