How to fix a character value returned as a numeric value in R?

Question

I am a new R user and having some difficulty when trying to rename certain records in a column.

My data have columns named classcode and fish_tl, among others. Classcode is a character value, fish_tl is numeric.

When classcode='OCAL' and fish_tl<20, I need to rename that value of classcode so that it is now "OCALYOY". I don't want to change any of the other records in classcode.

I'm running the following code:

data$classcode<-ifelse(data$classcode=='OCAL'& data$fish_tl<20,
                              'OCALYOY',data$classcode)

My problem seems to be with the "else" aspect: the code runs fine, and returns 'OCALYOY' as expected, but the other values of classcode have now been converted to numeric (although when I look at the mode of that field, it still returns as "character").

What am I doing wrong? Thanks very much!

It worked fine for me. I suspect that looking at `str(data)` will tell you more about this behavior. — Maiasaura, Oct 08 '12 at 21:43

score 0 · Answer 1 · answered Oct 08 '12 at 21:39

0

You can make the else part as.character(data$classcode). ifelse has some odd semantics with regard to the classes of the arguments, and it is turning your factor into it's underlying numeric representation. as.character will keep it as a character value.

answered Oct 08 '12 at 21:39

Brian Diggs

57,757
13
166
188

Thanks--I tried that already, but then it just returned TRUE for each value of classcode...I appreciate the quick reply! – user1729954 Oct 08 '12 at 21:46
Scratch that--it was is.character() I was using. As.character worked like a charm. Thank you so much! – user1729954 Oct 08 '12 at 21:52

score 0 · Answer 2 · edited May 23 '17 at 10:24

0

You may be getting tripped up in a factor vs character issue, though you point out that R thinks it's character. Regardless, wrapping as.character() around your code seems to fix the problem for me:

> ifelse(data$classcode=='OCAL'& data$fish_tl<20,
+        'OCALYOY',as.character(data$classcode))
#-----
 [1] "BFRE"    "BFRE"    "BFRE"    "HARG"    "OCALYOY" "OYT"     "OYT"     "PFUR"   
 [9] "SPAU"    "BFRE"    "OCALYOY" "OCAL"

If this isn't it, can you make your question reproducible by adding the output of dput() to your question instead of the text representation?

edited May 23 '17 at 10:24

Community

1
1

answered Oct 08 '12 at 21:41

Chase

67,710
18
144
161

Thanks--that fixed it. Sorry about the text representation...still trying to figure out how to post. I'll use dput() next time. – user1729954 Oct 08 '12 at 21:54

How to fix a character value returned as a numeric value in R?

2 Answers2