string splitting

[sanjay kumar]

Hi ,

I have the following scenario:
ArrayList<String> list;
list contains string in the following format:
www.xyz.com
test.xyz.com
img1.test.xyz.com
a.abc.com
etc...

I want to split each string in the arraylist like->
www xyz.com
test xyz.com
img1.test xyz.com

How should I follow this up??

I am totally new to regex

thanks!

[Henry Wong]

I want to split each string in the arraylist like->
www xyz.com
test xyz.com
img1.test xyz.com

How should I follow this up??

Well, what is the exact criteria? It doesn't look like you want to split on every ".". And since it doesn't, how do you determine so?

Henry

[Rob Spoor]

Well it looks like he wants to split on the second . from the end.

You can use String.lastIndexOf for finding the first, then the second, then use String.substring for splittint.

[Darryl Burke]

public class SplitOnSecondLastDot {
 
   public static void main(String[] args) {
      String[] inputs = {"www.xyz.com",
         "test.xyz.com",
         "img1.test.xyz.com",
         "a.abc.com"
      };
      String regex = "\\.(?=[^.]+\\.[^.]+$)";
      for (String input : inputs) {
         String[] outputs = input.split(regex);
         for (String output : outputs) {
            System.out.println(output);
         }
         System.out.println();
      }
   }
}

Regex explanation: a dot (quoted as it is a metacharacter in regex) with a non-capturing zero-width positive lookahead to one or more non-dots, followed by a dot, followed again by one or more non-dots, followed by the end of the String.

Replace both + with * if the dots are not compulsorily separated by non-dot characters e.g. if
abcd.efg..
has to yield
abcd.efg
.

[sanjay kumar]

Thanks all for the elaborate replies,
Yes Rob, you got it correct, I want to split from the second "." from the end

www.xyz.xom -> www & xyz.com
test.www.xyz.com0> test.www & xyz.com

[Darryl Burke]

Didn't feel like running the SSCCE I posted, huh?

Why do I bother...

[sanjay kumar]

Hi Burke,

Sorry, for not replying upto your expectation...
Do you need a "thank" you explicitly...
I dont think because you are doing more than a "very good job"

I did try your code , but what i went ahead was this

private static String extractDomain(String host) {
String refractoredHost;
int lastDot = host.lastIndexOf(".");
String token = host.substring(0, lastDot);
if (token.contains(".")) {
 
int secondLastDot = token.lastIndexOf(".");
refractoredHost = host.substring(secondLastDot + 1);
return refractoredHost;
 
}
return null;
}

I have another problem now

i am able to get the required in an arraylist, but how to count the occurence of each String ?

[Darryl Burke]

That's ok, even if you didn't use the regex solution it's more than welcome to know that you tried it.

To get any kind of a meaningful response, I think you'll need to explain just what you mean by

count the occurence of each String ?

[sanjay kumar]

I have the ArrayList<String> list;
For example : It contains xyz.com,xyz.com,abc.com,xyz.com,test.com..

Now I want a no of occurance of each string..
example
xyz.xom=3
abc.com=1
test.com=1

[Campbell Ritchie]

We don't simply give out answers.

Putting them into a List is easy. The counting is probably easiest done with another sort of data structure. If you aren't familiar with the collections framework, look at the Java Tutorials.

[Campbell Ritchie]

. . . and this is starting to look like a beginner's question.

[sanjay kumar]

I do have my code & pieces in place sir!!!
Im NOT ASKING for your code here..,
I have my solution ready, but doesnt look too optimal, I cannot post it here ..So just looking for some suggestions from some experienced people..
Seems that hurt you ..

[sanjay kumar]

And yeah, use of the "Collections Framework" makes most of my bread-n-butter!!!

[Campbell Ritchie]

We can only help you improve your code if we see what you have already.

[Piet Verdriet]

Originally posted by sanjay kumar:
And yeah, use of the "Collections Framework" makes most of my bread-n-butter!!!

Take it easy, sport.
You can use a java.util.Map<Key, Value> to store your url's in. The Key would be your url, and the Value would be an Integer (the number of times the Key occurred).

Before you add an url to your map you first check if it's not already in there. If it is, increase the counter (the Value) by one and if it isn't, just add it in your map with the initial value of 1.


Map tutorial: http://java.sun.com/docs/books/tutorial/collections/interfaces/map.html