Strange behavior of Table Row to Variable Loop

Continuing the discussion from Table Row to Variable Loop Start stops after first iteration:

In the example that @temesgen-dadi provided, the workflow works well with “CSV Reader”. However, the “Path” variable disappears if a) “File-Reader” node is selected b) you are working with a local file.

Same things happen with the “JSON reader” and a local file

Anyone understand why the “Path” variable disappears?

@usinlife welcome to the KNIME forum

I think the File Reader does not -yet- support the new Path Variables


Thanks @mlauber71 for the “Issues link”

I knew someone would say that :smiley: and that is why I linked to the example provided by @temesgen-dadi In that example - , there are 3 workflow examples and first example uses “Path to String (Variable)”

But here is what I found -

File reader node works when file names are :

    It does not work when file names are:

I think this is a bug…but maybe someone can verify it.

Hello usinlife,
the file reader requires a URI as input instead of a standard string so you need to convert the string to an URI first using the String to URI node. So you workflow would look like this:


The JSON Reader does not require the String to URI node so it would look like this:


Im sorry for the inconveniences and we are working on migrating more and more nodes to the new file handling framework which will then make this workaround unnecessary. Going forward all new and migrated reader and writer nodes will only support the new Path type.


Thanks Tobias,
does this mean STring to URI will be deprecated or are there still use cases for it?

Hello Daniel_Weikert,
as of now we do not plan to deprecate the String to URI node. It will take some time until all nodes from us and the community that work with files are converted to the new file handling framework and some might still require a URI.

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