How to check if a string is numbers? 2

[Petal]

I have a String test that I will make sure that only are numbers.

How do I do that?

 

[wushutwist]

Do this:

String test = "5";
boolean isNumber = false;
try {
   int i = Integer.parseInt(test);
   /* If you get here it is a number */
   isNumber = true;
}
catch (NumberFormatException) {
   isNumber = false;
}

if (isNumber) {
System.out.println(test + " is a valid number.");
}
else {
System.out.println(test + " is not a valid number.");
}

Wushutwist

 

[LeonTang]

I know there are people who prefer not to use try catch for such checkings so here is another example (although not as good in terms of memory wise)

String abc = "hello2";
int i=0;
for (i=0;i<abc.length();i++)
{
if (Character.isDigit(abc.charAt(i)))
break;
}
if (i < abc.length())
System.out.println(&quot;Invalid String.&quot;
else
System.out.println(&quot;Valid String.&quot;

Regards,
Leon