Hi! I'm new to knime and right at the beginning I have a problem with the 'Iterate List of Files' MetaNode.
All I did was to create a new workflow group and inside that create a new workflow. Then start with a 'List Files' node which provides text files that contain data. I connect the output to a column splitter to separate Location and URL. I connect one of the outputs to the 'Iterate List of Files' node's input and I get following error:
WARN File Reader 2:4:4 Can't access 'knime://knime.workflow/data.all'. (F:\Users\me\knime-workspace\SpatialLearning\SpatialLearning1\data.all (The system can not find the file specified))
When I try to configure the File Reader node I get the message:
Invalid settings:
With the current settings an error occurs: Can't access 'knime://knime.workflow/data.all'. (F:\Users\me\knime-workspace\SpatialLearning\SpatialLearning1\data.all (The system can not find the file specified))
Why is this error occuring and how can I fix it?
Background information: The ASCII .txt files each contain 2 sets of data that I want to seperate and build 2 tables. One table should end up containing the frist set of data from all the given files and the other table should contain the data of the second sets.
I got it to work. I did open the configuration of the File Reader inside the meta node and changed the knime://knime.workflow/data.all part in the valid URL entry box to one of the files (mustn't be empty, otherwise I got a java.lang.NullPointerException). Then I clicked the small box beside it an chose to use the variable URL.
Besides that I was even able to split the 2 data sets contained in the files by setting a limit to the rows read in via the advanced options.
After executing the workflow I had the content I wanted in the collected results of the meta node. Nice!
There won't be an easy always-works solution as the identifier of the variable that controls the file reader node changes with the data. It won't be possible to have a "iterate files" meta node that works without any further configuration.
I guess we should be just more clear in the meta node itself and add an annotation that points the user in the right direction, which is: open the config dialog and choose the name of the column that contains the locations (using the red variable button). You'll need to open the configuration anyway to specify separators etc.
The other problem (NullPointerException) is a bug that needs fixing. Fortunately it doesn't have side effects and is only a cosmetic problem.
We'll fix the meta node template in the next feature release.