J48 Weka in Knime error Cannot handle string class

KNIME Extensions
1

Hello everyone,

This is my first time using KNIME. I'm trying to classify some tweets into 3 sentiment class: positive, negative and neutral. The data includes 2 columns: the tweet and the manually classified class. In an attempt to increase the accuracy, I used J48 (3.7) node from the KNIME node repository, but it failed with the following error:

ERROR J48 (3.7)            0:293      Execute failed: Weka classifier cannot work with given data. Reason: weka.classifiers.trees.J48: Cannot handle string class!

How can I resolve this problem with this node? The actual workflow I am working on is in the attachment and KNIME 3.1.1 is currently being used.

Thank you!

2

Hi,

would be better if you export your workflow with some datas.

Fabien
 

3

Hi,

my bad. Certainly it is better to go with data. Here you are. The workflow with Weka J48 Learner / Predictor. I understand that the "Document Class" is now of String type. How can I change it / is there anyway that I can get J48 or other Weka learner to work with this kind of data type e.g. weka random forest?

Thank you very much.

Duc

4

Hi see the workflow in attachment.

Just filter the document column.

Best regards,

Fabien
 

5

Hi, Thank you very much :). It's working

6

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