Regex or Exception Handling?

Question

Which one of the following is a better practice to check if a string is float?

try{
 Double.parseDouble(strVal);
}catch(NumberFormatException e){
 //My Logic         


        

Answer 1

If you use parseDouble, you will end up with what Mark said, but in a more readable way, and might profit from performance improvements and bug fixes.

Since exceptions are only costly when they are thrown, there is only need to look for a different strategy if you

• expect wrong formats to happen often
• expect them to fall in a specific pattern which you can catch faster and beforehand

In the end you will call parseDouble either, and therefore it is considered alright to use it that way.

Note that your pattern rejects 7. as a Double, while Java and C/C++ don't, as well as scientific notation like 4.2e8.