@mariesylvia maybe you could provide us with some dummy data that would contain the tasks you have and also the outcome so we could develop a solution and you can check it. I am sure the forum will be able to help.
Would you do this for one specific column or several ones. Since KNIME is based on Java you always have the full power of Java at your fingertips. It might be a little bit of try and error first but you will then have the full range of options - and the KNIME forum is always there to help.