Well today, I was trying to load a csv file in Weka when I got the dreaded error message . I had seen this java error message “java.io.IOException: wrong number of values. Read 28, expected 18, read Token[EOL], line 25 “on an earlier occasion too and that time having no clue on how to fix it I ended up deleting most of the columns of the dataset. Perhaps a brief background first that causes this problem message. Look, if you have very noisy data especially if you are trying to consolidate a dataset from a datasource then typically you will be coping several columns and pasting them into a .xls or CSV format file. Well, I was attempting to do something similar too.
So when I fired up Weka and wanted to convert the .csv file to .arff format using Weka Arff viewer, I got the above error. In order to solve it all you have to do is to check for any trailing comma signs at the end of the text or any double quote sign in between or anywhere within the text or simply put any forms of punctuation marks within your dataset. The cause for this error is shown in the picture.
As you can see this text in data contains all the punctuation marks. So to resolve this java error, Remove any punctuation marks in your dataset and then try loading the data again in Weka. it will work.
Hope this helped you.