checking number string

[lowbk]

hi, i need some advice on checking number string.
eg input is "1234" and i need to verify if it is numeric.

currently i go through each character within to see if it is a digit; if all are digits then it will return true. but this looks very long-winded.

can anyone advise on a much neater way?
thanks

 

[raochetan]

try using 'Integer.parseInt(String num)' within try block and catching the NumberFormatException

Hope it helps

regards
raochetan

 

[MarsChelios]

You can try to match it with a regular expression.

someString.matches ("\d+")

will return true for one or more digits and false for anything that is not completelty numeric. If you are using floating point, try

someString.matches ("\d*.?+\d*")

. It allows for the decimal char and numbers in front and behind.

Hope this helps,
MarsChelios

 

[lowbk]

marschelios, i looked through the java api but there is no method "matches". is this method from the api or is it a self-defined one?

 

[MarsChelios]

The matches method is in the String class in JDK 1.4.

 

[MarsChelios]

Hi all,
I found another error with the Regular Expression for floating-point numbers. The . character is a special character which allows any character to replace it. To use the actual ., prefix it with \.
The Regular Expression:

("\d*.+\d*&quot

should be changed to:

("\d*\.+\d*&quot

Hopefully, this is the last error I find with this.
MarsChelios

 

[MarsChelios]

Hello all,
My FAQ on Regular Expressions has been posted, Let me know what you guys think.

MarsChelios