Nightly Build - How to create "path" flow variable?

I’m trying out the new Excel Writer in the Nightly build I downloaded today (4.3.0). I really like this node, and the ability it has to add multiple sheets to an Excel file. Huge improvement!

However, the node only accepts flow variables of the type “path” for “file_selection”. This appears to be a new flow variable type, right? I’m trying to convert a string flow variable, with a value of “C:\Data\KNIME\Test.xlsx” to a path variable, but I can’t figure it out. Any tips?

Also, I’d be curious to understand the advantage of creating a new flow variable type, instead of just using a string flow variable for file selection, as has been done in the past.

Also, is this the right place to post questions/comments about the Nightly Builds?


Hi @stevelp,

Not quite, you can just post them in the general section. This sub forum is meant for people who develop their own KNIME extensions. I put your post into the right section.



In the KNIME Labs (IO/Other) is a node called “String to path” have you try it



glad to hear that you like the new excel writer / sheet appender :).

The advantage of this flow variable is that it does not only control for the location, but also the selected file system, i.e., when open the dialog you also see at the top the write to drop down. A String flow variable cannot control for this. If you, e.g., use the Create File/Folder variable node and in the beginning you write relative to -> workflow data area and at some point you decide to write to your Local FS all you have to do is adapt this node, but none of the nodes downstream. A String flow variable would not be sufficient.

Regarding how to create these variables from a string or get a string flow variable from a path you can use the String to Path (Variable) or Path to String (Variable) nodes.


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Thanks to everyone for your responses. I installed the nightly build on a personal computer and kept forgetting to check this solution. I had tried using a string to path node before and it didn’t seem to work (maybe I wasn’t using the right onw). However, with the stable release of KNIME 4.3, using the String to Path node works perfectly!


Is there any plan to make the String to Path (Variable) functionality available in v4.2? The labs nodes are great but without Path as a flow variable, we lose much of the power they bring.

No this is not planned, but we released 4.3 last Sunday. So if it is an option for you you could simply update it the newest stable version

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