[BioC] classifier using R

James W. MacDonald jmacdon at med.umich.edu
Sat Jun 24 22:48:15 CEST 2006

Hi Nadege,

Nadege Nana wrote:
> I' trying to write a classifier usisn R
>     I have microarray data(.xls), i saved the data as   .txt, and import them in R with read.table()
>     I  first tried to calcute knn: but i always receive the failure: Data have  differents length, when i check their Length there are same.
>      How kann i calculate one of these classifiers sing   R:
>     knn- classifier
>     Bayes-classifer
>     Hidden Markov Modell
>     Neural net

The problem you are experiencing is due to the fact that classical 
statistics almost always envision the samples in rows and the 
observations in columns. For microarray data, the convention is the 
opposite (samples in columns, genes in rows). In order to use these 
methods, you have to first transpose your matrix of data, and then 
things should work.



James W. MacDonald
University of Michigan
Affymetrix and cDNA Microarray Core
1500 E Medical Center Drive
Ann Arbor MI 48109

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