Write text with variables to a file

[mpreusse]

I use KNIME to process data and create a CSV file that is used in a downstream application.

For the downstream application I need some metadata from the workflow. Is there a way/node to create a longer text file using flow variables?

The idea behind this is to create commented queries for the downstream application and export them to a file next to the CSV data.

[mlauber71]

@mpreusse you could extract several meta information from the workflow, the files you use or the current table/data in knime.

Extract Context Properties

Extract Table Dimension

Extract Column Header

(And there are more)

You can then store that into a table, if you have a variable you can convert that to data. The data you can then store in any format you like.

Variable to Table Row

Variable to Table Column

In this example you can see how to extract meta information from a file:

more fun with URI, URL and File Paths - work with the new Path variable...

[mpreusse]

Thanks @mlauber71 for the pointers!

I begin to understand how I can handle metadata. I also found the Table Creator node that I can use to store comments and the queries I mentioned.

There is one thing I did not find yet:
Is there a way to create a variable or table and store a string with a flow variable? Something like:

Some text here that uses $some_variable_from_flow

[mlauber71]

@mpreusse glad you liked the links

If you just want to create texts you could use a Java Snippet (simple) either to create a Flow variable or a column, which then you could convert into a column in a table or a Flow variable.

Simple Java snippets have these

return <your content>;

Syntax where the content can also contain results from a Flow variable. With a little planning and experimenting you have nearly endless possibilities to combine information.

KNIME - small useful Java Tasks and other little helpers – mlauber71

java snipped simple if else

I built this example from the previous one where you could use a combination of columns and Flow Variable in a simple Java Snippet. It might serve as another inspiration. [image] The code is like this: // make the incoming Flow Variable into a Java variable double v_input_factor; v_input_factor = $${Dinput_factor}$$; // convert the double Java variable into a string to use in the code // https://www.journaldev.com/18380/java-convert-double-to-string String v_input_factor_string = new Stri…

Another powerful tool is the

String Manipulation

Of you could just use the Rule engine, which also is quite handy:

Rule Engine

[mpreusse]

Thanks @mlauber71, I did not know about the simple Java Snippet before, that is really flexible.