[R] PCA on high dimentional data
    mail me 
    mailme842 at googlemail.com
       
    Sat Dec 10 16:56:35 CET 2011
    
    
  
Hi:
I have a large dataset mydata, of 1000 rows and 1000 columns. The rows
have gene names and columns have condition names (cond1, cond2, cond3,
etc).
mydata<- read.table(file="c:/file1.mtx", header=TRUE, sep="")
I applied PCA as follows:
data_after_pca<- prcomp(mydata, retx=TRUE, center=TRUE, scale.=TRUE);
Now i get 1000 PCs and i choose first three PCs and make a new data frame
new_data_frame<- cbind(data_after_pca$x[,1], data_after_pca$x[,2],
data_after_pca$x[,3]);
After the PCA, in the new_data_frame, i loose the previous cond1,
cond2, cond3 labels, and instead have PC1, PC2, PC3 as column names.
My question is, is there any way I can map the PC1, PC2, PC3 to the
original conditions, so that i can still have a reference to original
condition labels after PCA?
Thanks:
deb
    
    
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