Rename columns in list of dataframes in R

Question

I have list of dataframes and I want to change column name in each dataframe

my_list <- list(one = data.frame(a = 1:5, lag_a = 1:5, lag_a = 1:5, lag_a = 1:5, lag_a = 1:5), 
                wo = data.frame(a= 1:5, lag_a = 1:5, lag_a = 1:5, lag_a = 1:5, lag_a = 1:5),
                three = data.frame(a = 1:5, lag_a = 1:5, lag_a = 1:5, lag_a = 1:5, lag_a = 1:5))

my_list <- map(my_list, ~ rename_with(., ~ ifelse(
    grepl("lag_", .), paste0("a", 4:1), . 
  )))
my_list[1]
> my_list[1]
$one
   a a3 a2 a1 a4
1  1  1  1  1  1
2  2  2  2  2  2
3  3  3  3  3  3
4  4  4  4  4  4
5  5  5  5  5  5

But I want the colnames in each data frames a, a1, a2, a3, a4 in order. But it cant because automatic the first one in R be tagged as one(?). Maybe.

Actually in real my data i want to rename be a, a1,a2,a3,a4,a5,a6,a7,a8,a9,a10,a11,a12. But I try still cant

Thank you for helping

Answer 1

Using starts_with instead of an ifelse you could do:

library(dplyr)
library(purrr)

my_list <- map(my_list, ~ rename_with(., ~ paste0("a", 1:4), starts_with("lag_")))

my_list[[1]]
#>   a a1 a2 a3 a4
#> 1 1  1  1  1  1
#> 2 2  2  2  2  2
#> 3 3  3  3  3  3
#> 4 4  4  4  4  4
#> 5 5  5  5  5  5

Or using base R you could do:

base <- lapply(my_list, function(x) { 
  is_lag <- grepl("^lag_", names(x)) 
  names(x)[is_lag] <- paste0("a", seq(sum(is_lag))); 
  x 
})

base[[1]]
#>   a a1 a2 a3 a4
#> 1 1  1  1  1  1
#> 2 2  2  2  2  2
#> 3 3  3  3  3  3
#> 4 4  4  4  4  4
#> 5 5  5  5  5  5