[R] Strange column shifting with read.table

Noah Silverman noah at smartmediacorp.com
Mon Aug 3 08:31:23 CEST 2009


Thanks for the continued support.

I've been working on this all night, and have learned some things:

1) Since I'm really committed to using an SVM, I need to skip the 
examples with missing data.  I have a training set of approximately 
22,000 examples of which about 500 have missing values.  Not a 
significant number to skip.

2) I believe the heart of my problem is based on the behavior of the 
scale function.  If I pass scale a single value or a list of values that 
are all 0, then it returns NaN.  I am scaling data by groups, and some 
of them have all 0 for some columns.  So, even though I start with 
"clean" data containing no NA values, I wind up with some after the 
scale operations.  I just posted a separate message asking for help on this.

3) R is forcing me to look at details of the experiment that were never 
considered in RapidMiner (RM).  In fact, I'm quite suspicious as to how 
RM is handling these issues since they are hidden within the "black box" 
of their GUI.

4) The learning curve is steep, but worth it!!

If there was a "R" class in Los Angeles, I'd sign up right away...

Thanks again for all the help.


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