Reclassify string values
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