I am trying to perform some simple text analysis using KNIME. My process begins by using a normal 'XLS reader' or a 'text reader', followed by 'row filter' which executes fine. This step is followed by 'Strings to document' to convert every string into a document. Following this step, no steps execute. I have tried using 'POS Tagger', 'BoW Creator', 'Row Filter', 'Number Filter' etc, but each one of these gives me a 'NULLPointerException'. Why is this the case?
My input document is a text file with about 300,000 rows coming from the database. I have checked that none of the rows in the file is NULL.
How can I get rid of this error?
This is URGENT, any help would be highly appreciated.
which KNIME version are you using? Could you please send me the stack trace. You can do this by setting the log level for the KNIME GUI to debug (File->Preferences->KNIME->KNIME GUI) and copy paste the stack trace from the console, or copy paste it from the log file (..path to your workspace/.metadata/.log). Thank you.
btw. since KNIME Textprocessing v. 2.9 you can apply preprocessing nodes, such as Stopword filter etc. directly on the list of documents, which is a lot faster than preprocessing a bag of words. E.g.:
... ->Strings to Document->Stopword filter->Number filter->...->BoW
Use the BoW node after the preprocessing nodes to create a bag of words.
this might be the same problem as posted here:
It is a bug. However there is a workaround to avoid the error. Please see the post for the workaround.