replace empty fields

[nicole]

I want to replace empty fields with a value in a column, filled fields should be preserved.
The problem is that empty fields are not recognized, only an empty field with “?” Is recognized. I found some hints in the forum, but they did not work.

Otherwise I do this via the node rule engine:
MISSING $company$ => “NEW”
TRUE => $company$

Does somebody has any idea?

[ScottF]

You could use the toNull() function in the String Manipulation node to convert blanks to missing values, and then handle all missings at once with the Missing Value node.

[nicole]

Thank you very much.

[armingrudd]

Hi,

Beside the solution that @ScottF has provided for converting the empty (blank) cells to missing, I can suggest using “Column Auto Type Cast” node in which you can do the trick for several columns at once by setting the “Missing value pattern” option to <empty>. (Thanks to @Iris for teaching this to me at replace empty cell with missing (?) globally in table)

Best,
Armin

[nicole]

Hi Armin,

this is great, and thank you for sharing the other chat too. It´s very helpful for me.
I wonder why I did not find this chat yesterday in my search in the forum. I’ve read and tried so much, but not the simple one.

Thanks,
Nicole

[mlauber71]

If you ever need to do things the other way round and assign missing values, @ipazin had an idea for that too:

Replace specific row values of a column with NULL values

Sometimes Rule Engine, Variables and Null values can be tricky. I have added an example where you could define your own replacement rules. Age gets replaced by NULL and gender by “NA”. Please note: there is no generic NULL in the Rule engine but ipazin came up with an clever solution (Create or replace column with NULL values) - create a column with just missing and use that you would always need a TRUE rule that covers everything else. If you do not have one you will create missing values yo…

[agaunt]

@nicole

Otherwise I do this via the node rule engine:
MISSING $company$ => “NEW”
TRUE => $company$

Have you tried the following rule:
$company$ = "" => "NEW"

[armingrudd]

I could remember this topic, but usually I use the bot I’ve built for KNIME forum (https://github.com/armingrudd/KNIME-forum-Selena-bot) to find similar topics.
I hope I would be allowed to run it in forum soon. The bot (which I call it @Selena now) automatically finds similar topics and suggests them to users.