"Issues with regular expressions"

Original message from SourceForge forum at http://sourceforge.net/forum/forum.php?thread_id=2034662&;forum_id=390413

The following regular expression works in RapidMiner: '[A-Z][a-z]+', when applied to any text, to extract words that begin with an upper case. 

However, if I add any space definition, it does not work. For example: '[A-Z][a-z][ ][A-Z][a-z]+', does not get recognized as a valid regular expression.

The same expressions work well in other regex text editors.

Any ideas on why RapidMiner is not recognizing the space definiton?

Thanks,

FDR


Edit by topic starter:

I found the answer shortly after posting this; spaces seem to be defined by \s as in:
'\s[A-Z][a-z]+\s[A-Z][a-z]+'

The expression above works. However, it does find only the first occurrence of the match. Any ideas on how to get all occurrences?


Answer by Ingo Mierswa:

Hi,

the regular expressions should be the same as they are supported by Java as explained here:

http://java.sun.com/j2se/1.5.0/docs/api/java/util/regex/Pattern.html

I am not too sure but it might be that capturing groups can help here:

http://java.sun.com/j2se/1.5.0/docs/api/java/util/regex/Pattern.html#cg

Cheers,
Ingo