Regular Expression

[faisal hameed]

I want to match the decimal values by using regex matcher of java.How can i do that?

Examples.

3
3.3
34.009
0.34

but not
.3

[Kiaamaa Liammes]

I am not sure whether I followed the requirement correctly or not, this code will not match any expression which does not have anything before this decimal

 import java.util.regex.*;

public class SampleRegex
{
	
   public static void main(String[] params)
   {
	   String[] param = {"3","3.3","34.009","0.34",".3"};
	  
      Pattern pattern = Pattern.compile("[-+]?[0-9].*[0-9]*");
     
      for(String test : param){
    	  
    	  Matcher matcher = pattern.matcher(test);
    	  
    	  if(matcher.matches()){
                      System.out.print("\nMatch :" + test);
    	  }
    	  else
          System.out.print("\nNo match :" + test);
       }
    	  
      }
}  

[faisal hameed]

Thanks for your response.
But how i can modify it so that it can accept only one dot(.) anywhere.

[Henry Wong]

     Pattern pattern = Pattern.compile("[-+]?[0-9].*[0-9]*");  

Just "eyeballing" this, but won't this also match something like.... "1 flew over the cuckoo's nest"? I don't think this is what the OP wants.

Henry

[Henry Wong]

faisal hameed wrote:Thanks for your response.
But how i can modify it so that it can accept only one dot(.) anywhere.

This is generally what happens with regular expressions -- when you try to get help from the net, but don't understand the code that you got. You wind up not being able to modify it, or even understand if it works or not.

You really need to start with a tutorial on regex, in order to understand it. Otherwise, you wind up using code that you don't understand, and that is *never* a good thing.

Anyway...

Pattern pattern = Pattern.compile("\\d+\\.?\\d*");  

Henry

[Kiaamaa Liammes]

faisal plzz refer this link and try for the regex you want RegEx Tutorial

[Mohamed Sanaulla]

I feel that Regular expressions are something which are very useful to learn. I remember listening to one of the speakers at a local JUG meet about this book- Mastering Regular Expressions. Supposed to be really useful book.

[Stephan van Hulst]

They are indeed very useful. But at the same time, I think people resort to them too quickly to solve problems that can be solved more elegantly using 'conventional' code.