Use Row Filter with regular expressions

KNIME Analytics Platform
#1

Hi,

I wonder whether it is possible to use "!" regular expressions in the Row Filter Node.

I have a table and I want to remove all rows that contain "Unspecified" in the column "reference".

For that I used Row Filter > Configure > select column to test = reference

then match criteria > use pattern matching > pattern = !Unspec.*

and checked "regular expressions".

It works without the "!" getting all the Unspecified entries, but I want the reverse.

!(Unspec).*

(!Unspec).*

everything leads to an empty table.

Is "!" not functional in the RegEx implementation of KNIME?

#2

You can choose whether to include or exclude rows in the left of dialog. Just use the "positive" pattern and then exclude the matching rows.

Note that there is no such thing as a global negation for regular expressions. You can only do negative lookaheads, but this is higher regex magic.