Remove Column According to a Constant Cell Value

[goygokhan]

Hi all,
I have a specific problem. I need to remove a column in the table which it contains one constant(for example a number value like 0). I’m not talking about the whole column here. Even if we have only one value which is equal to constant value,I need to remove that column. Does this doable with KNIME ?
Best,
-GG

[andrejz]

Hi,

If you don’t want to remove the entire column then you want to remove only rows that contain that specific value … for this use use “Row filter” node (https://nodepit.com/node/org.knime.base.node.preproc.filter.row.RowFilterNodeFactory)

But if you want to remove the entire column with at least one value that is equal to the constant look here filter a column based on value

[andrejz]

Hi.

First you have to make a list of columns that have certain value and then filter this columns from the original table. Here is a small example filter column value.knwf (32.5 KB).

Hope is useful for you

[ipazin]

Hi there @goygokhan,

welcome to KNIME Community!

Not a common request you have there. This could be easily done with Constant Value Column Filter node if it has threshold option (absolute or relative). Can you tell us a bit more about use case? Do you have numbers or strings or both in table? Do you apply it to all columns? How big is the table?

Br,
Ivan

[goygokhan]

Hi @ipazin ,
Below you can find a chunk of data and in some columns I have 0 values as you can see. And I want to remove all columns if it contains 0(like A1CF,A2BP1 etc.). I hope this image can be useful. By the way “Constant column value filter” node didn’t help me because it removes a column if it’s only contains anything but 0.

[ipazin]

Hi @goygokhan,

you can try following approach:

• calculate minimum for each column using Math Formula (Multi Column) node (if you have negative values use abs() function also)
• use Constant Value Column Filter node to filter out columns that are 0.0
• finish it with Reference Column Filter node

Like this:

Give it a try and if having trouble can create a workflow example.

Br,
Ivan