[R] replace string values with numbers

[David Winsemius]

On Sep 26, 2012, at 12:52 PM, JiangZhengyu wrote:

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> Hi everyone, I have a data frame Gene with SNPs eg.   P1 P2 P3 
> CG CG GG
> -- --  AC 
> -- AC CC
> AC  --  AC I tried to replace all the GG with a value 3.    Gene[Gene=="GG"]<-3 It always give me:  Warning in `[<-.factor`(`*tmp*`, thisvar, value = 3) :
>  invalid factor level, NAs generated Does any know if there is anything wrong with my code?

You are trying to replace a factor value with a level that it doesn't have. Hence that particular very informative error message.

-- 

David Winsemius, MD
Alameda, CA, USA