Changing an ID name by location in R-CodePudding

I have 2 repeated IDs in my data frame, and I want to change the name of one.

When I use revalue function by dplyr, the new name is assigned to both.

That's why I wanted to do it by specifying the location of the ID by column and row and then changing it but I couldn't find how to do it.

In short, my question is how can I change only one ID(element)'s name if it is repeated twice in a data frame?

Edit: To be more specific let's say my data is this-

Value <- c(12,23,4,5)
ID <- c("A", "B", "A", "C")
Score1 <- c(3, 2, 1, 4)
Score2 <- c(4,5,9,10)
mydf <- data.frame(Value, ID, Score1, Score2)
mydf
# Value ID Score1 Score2
1    12  A      3      4
2    23  B      2      5
3     4  A      1      9
4     5  C      4     10

I want to change the Second "A" to "A-1".

(It could be a very basic question, I am new in R, sorry :D)

CodePudding user response：

Assuming you would want subsequent As (if then have more than one duplicate) to be sequentially numbered, then make.unique works well here:

make.unique(mydf$ID)
# [1] "A"   "B"   "A.1" "C"

If you must have it with a dash instead of a period, then

sub(".", "-", make.unique(mydf$ID), fixed = TRUE)
# [1] "A"   "B"   "A-1" "C"

Either way, this can be easily reassigned back into mydf$ID.