rename the level of a catgorical variable

[alexgalli]

Hallo R Studio Community,
I am having a strange issue:
not receveing any error by running the following code,

' data$dgn[data$dgn == "AHN"] <- "ALF" '

it comes out that the level is not changed and the new name desired is not set.

I tried to change the class of the variable from character to factor, and nothing changed.

Any suggestion you can give me? Thanks!!

[sigbert]

Hi,

it should work if "AHN" is really in your data:

dgn <- letters[1:10]
dgn
dgn[dgn=="c"] <- "C" # replacement done
dgn
dgn[dgn=="z"] <- "Z" # no replacement done, since "z" is not in dgn :(
dgn

[103o]

Hello,

I think you got this issue because your variable is a factor and "ALF" is not a level of the variable.
You can try this for exemple:

#convert your variable into Character
data$dgn<-as.character(data$dgn)
#run your changes 
data$dgn[data$dgn == "AHN"] <- "ALF"
#Then reconvert the variable into factor
data$dgn<-factor(data$dgn)

```r

Thanks

[103o]

Hello,

You can also try this:

levels(data$dgn)<-list("AHN"="ALF",      "a"="a",    "b"="b",  ......,  "x"="x")

[alexgalli]

you are right! there was a comma I did not see, now I am fixing the issue. Thanks!!