Message-ID: <CA+hbrhX5psvDCjOgFhvA+BFsVP9113K=ZFcXOXBVaR0yNdo-WQ@mail.gmail.com>
Date: 2011-11-03T19:13:32Z
From: Peter Langfelder
Subject: Reclassify string values
In-Reply-To: <4EB2E495.8070602@zevross.com>
On Thu, Nov 3, 2011 at 11:59 AM, Zev Ross <zev at zevross.com> wrote:
> Hi All,
>
> Is there a simple way to convert a string such as c("A", "B" ,"C", "D") to a
> string of c("Group1", "Group1", "Group2", "Group2"). Naturally I could use
> the factor function as below but I don't like seeing that warning message
> (and I don't want to turn off warning messages). Perhaps a function called
> "reclassify" or "recategorize"?
>
> Zev
>
> x<-LETTERS[1:4]
> x2<-as.character(factor(x, levels=LETTERS[1:4], labels=rep(c("Group1",
> "Group2"), each=2)))
>
> Warning message:
> In `levels<-`(`*tmp*`, value = c("Group1", "Group1", "Group2", "Group2" :
> ?duplicated levels will not be allowed in factors anymore
If you want to "translate", why not first build a translation table
tt = cbind(LETTERS[1:4], c("group1", "group1", "group2", "group2"))
then apply it on an example:
xx = sample(LETTERS[1:4], 20, replace = TRUE)
translation = tt[ match(xx, tt[, 1]), 2]
> translation
[1] "group2" "group2" "group2" "group2" "group2" "group1" "group2" "group1"
[9] "group2" "group1" "group1" "group2" "group2" "group2" "group1" "group2"
[17] "group2" "group1" "group1" "group2"
Or did I misunderstand your intent?
Peter