Trim list of words from the end of strings

Hi all!

So I have the following table:

and I want to filter the strings from the column “DESCRIPTION”, by removing everything after certain words. In the example above I want to trim the strings after the words “ATTACHING” and “OPT”. So the output would look like this:

For this, I used the node Cell Splitter, where I split the “DESCRIPTION” column on those words and then keep the first column and delete the second one. Something like this:

However, as there are a lot of words that I want to trim on, this method becomes inefficient. Any ideas for a better way to do this? Ideally, I would provide a list of words as input and based on all these words the strings would be trimmed. The workflow that I used and the input file can be found below.

B737 IPC R6 Data Extraction.knwf (42.4 KB)
00000001_001_of_325 v4.xlsx (92.2 KB)

Any help/insight would be appreciated. Thank you!

hI @mmelbaghdadi ,
maybe this workflow can solve the problem. The words “ATTACHING”, “OPT” etc. must be written in a table, then they are concatenated using the “pipe” as a separator. The resulting string is used in a regexReplace expression
KNIME_temp.knwf (11.9 KB)

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@duristef thank you for your help.

I tested the workflow, it indeed worked with words. Unfortunately, when I used inputs such as: “(V1” and “(CONTINUED)”, it removed the whole string. I assume this is caused by the parenthesis. Is there a way to trim these inputs as well?


it happens for two reasons

  • you have parentheses in your “words”. Parentheses (every kind of) have a special meaning inside regex, so you have to escape them inside the string you’re looking for, preceding them by a backslash: \( So for example “(CONTINUED)” must become “(CONTINUED)”. Same is true for other special characters, such as “?”, “*” and “.”.
  • you are searching for both whole words and first characters of words, and that changes the pattern to be searched for by the regexReplace expression. Try replacing it with
    strip(regexReplace($Description$, "^(.*?[\b| ])("+$${Swords}$$+").*$", "$1"))

Hi @duristef thank you for your response. I have used the new expression but for some reason it still deletes the column.
Here is your workflow (adjusted):
Trim.knwf (12.1 KB)

You didn’t escape the round brackets, as I told you

this is the result

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@duristef that works for now. Your time and effort are appreciated. Thank you!

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