Issue

This Content is from Stack Overflow. Question asked by John M.

I’m dealing with a quite complicated data frame. I’m trying to rename its columns by adding some terminal digits to each column several times. How can I do that?

Let me make an example:

df=data.frame(disease=c("HB1","HB2","HB3","HB4"),
          region="AZ",
          hospitalAZ=runif(4),
          hospitalAZ=runif(4),
          hospitalAZ=runif(4),
          hospitalAZ=runif(4))

This is just a stupid example. The outcome should be: the columns after “region” should be named HospitalAZ1, HospitalAZ2, HospitalAZ1, HospitalAZ2. I looking for a parsimonious way of adding, in this case, 1 and 2 to the 4 columns with repetition (2 times in this case). Then, how can I extract the outcome in an xls file?

Solution

We could use rename_with

library(dplyr)
library(stringr)
df <- df %>% 
    rename_with(~ make.unique(str_c("HospitalAZ", rep(1:2,
       length.out = length(.x)))), starts_with("hospitalAZ"))

-output

 disease region HospitalAZ1 HospitalAZ2 HospitalAZ1.1 HospitalAZ2.1
1     HB1     AZ   0.1796734  0.28729264     0.8549300     0.8486733
2     HB2     AZ   0.8518319  0.03438504     0.5909983     0.8378173
3     HB3     AZ   0.3961885  0.67294967     0.4627137     0.5484321
4     HB4     AZ   0.9955195  0.38767387     0.1961428     0.6010028

NOTE: matrix can have duplicate column names, but data.frame duplicate column names are not recommended and in tidyverse the duplicates can result in error

In base R, we may do

i1 <- startsWith(names(df), "hospitalAZ")
names(df)[i1] <- paste0("HospitalAZ", rep(1:2, length.out = sum(i1)))
> df
  disease region HospitalAZ1 HospitalAZ2 HospitalAZ1 HospitalAZ2
1     HB1     AZ   0.1796734  0.28729264   0.8549300   0.8486733
2     HB2     AZ   0.8518319  0.03438504   0.5909983   0.8378173
3     HB3     AZ   0.3961885  0.67294967   0.4627137   0.5484321
4     HB4     AZ   0.9955195  0.38767387   0.1961428   0.6010028

This Question was asked in StackOverflow by John M. and Answered by akrun It is licensed under the terms of CC BY-SA 2.5. - CC BY-SA 3.0. - CC BY-SA 4.0.