[R] Setting elements in data frame

[Peter Dalgaard BSA]

Christian Hoffmann <christian.hoffmann at wsl.ch> writes:

> Hi all,
> 
> I have a problem which I am biting my teeth into unsuccessfully:
> 
>  (x <- data.frame(S1=c("a","b","d","F"),N1=c(2,4,6,9),N2=c(6,NA,0,6)))
>   S1 N1 N2
> 1  a  2  6
> 2  b  4 NA
> 3  d  6  0
> 4  F  9  6
> > is.na(x)
>      S1    N1    N2
> 1 FALSE FALSE FALSE
> 2 FALSE FALSE  TRUE
> 3 FALSE FALSE FALSE
> 4 FALSE FALSE FALSE
> 
> No I want to be able to do:
> 1) Setting all elements == 6 to 6000
> x[x == 6] <- 6000
> Error in [<-.data.frame(*tmp*, x == 6, value = 6000) : 
> 	matrix subscripts not allowed in replacement

This seems to work, save for a (sort of spurious) warning that 6000 is
not a valid replacement value for the factor column:

x[,]<-lapply(x,function(z){z[z==6]<-6000;z})

(Why the comma? Search me...)

> 2) Setting all elements == NA to -1000
> x[is.na(x)] <- -1000

Same story..

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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