I work with Excel-file, which contains several sentences. I would like to generate new attribute (I use "Generate Attribute" operator), which returns (“true or false”) if the sentence contains the chain of numbers with white spaces between them (e.g. 234 45 56 or 2.3 34 56 5.6 or 2,345 56,67 34 2013 or 23% 34% 56%..). So a chain can contain different numbers, e.g. with percent or decimal points) and can be of different length. I have used the function “match nominal regex” (match(sentences,"\d+\s+\d) to do this. However, I faced the problem that Rapidminer does not recognize the escape (\) character. How do I change my Regex to make it work? Besides I would appreciate some help on my regex, I am not sure how to capture the decimal values.