jlfmssm wrote:
>
> Sorry, I didn't get it.
> I made a simple example to explain what I want
>
>> x=c(1,2,4,4)
>> y=c("A",1,2,"A")
>> test<-as.data.frame(cbind(x,y))
>> test
> x y
> 1 1 A
> 2 2 1
> 3 4 2
> 4 4 A
>> test[test$x==4,]$y<-'B'
> Warning message:
> In `[<-.factor`(`*tmp*`, iseq, value = c("B", "B")) :
> invalid factor level, NAs generated
>> test
> x y
> 1 1 A
> 2 2 1
> 3 4 <NA>
> 4 4 <NA>
>
> actually, what I want is
>
>> test
> x y
> 1 1 A
> 2 2 1
> 3 4 B
> 4 4 B
>
Try this
x=c(1,2,4,4)
y=c("A",1,2,"A")
atest <- data.frame(x=x,y=y)
str(atest)
atest
levels(atest$y)[4] <- 'B'
atest[atest$x==4,]$y <- 'B'
str(atest)
atest
This gives the following output
> x=c(1,2,4,4)
> y=c("A",1,2,"A")
> atest <- data.frame(x=x,y=y)
> str(atest)
'data.frame': 4 obs. of 2 variables:
$ x: num 1 2 4 4
$ y: Factor w/ 3 levels "1","2","A": 3 1 2 3
> atest
x y
1 1 A
2 2 1
3 4 2
4 4 A
> levels(atest$y)[4] <- 'B'
> atest[atest$x==4,]$y <- 'B'
> str(atest)
'data.frame': 4 obs. of 2 variables:
$ x: num 1 2 4 4
$ y: Factor w/ 4 levels "1","2","A","B": 3 1 4 4
> atest
x y
1 1 A
2 2 1
3 4 B
4 4 B
Berend
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