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.
HTH,
Jim
--
James W. MacDonald
University of Michigan
Affymetrix and cDNA Microarray Core
1500 E Medical Center Drive
Ann Arbor MI 48109
734-647-5623
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Are the data all numeric? Are you saving the xls file as
comma-limited or tab delimited.
If the data include characters, you should be aware that some
characters such as spaces and slashes in the columns might cause
problems. I always use a global search to remove these characters.
The most robust way to read the data is to save as tab delimited and
use read.delim.
--Naomi
At 01:36 PM 6/23/2006, 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
>
> Thanks for your help
>
>
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>
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Naomi S. Altman 814-865-3791 (voice)
Associate Professor
Dept. of Statistics 814-863-7114 (fax)
Penn State University 814-865-1348
(Statistics)
University Park, PA 16802-2111
