Same Column Names in flextable in R - r

Question

I am trying to create a 'flexable' object from the R package "flextable". I need to put same column names in more than one columns. When I am putting them in the the "col_key" option in the function "flextable" I am getting the error of "duplicated col_keys". Is there a way to solve this problem?
a<-c(1:8)
b<-c(1:8)
c<-c(2:9)
d<-c(2:9)
A<-flextable(A,col_keys=c("a","b","a","b"))
This is the example code for which I am getting the error.

Answer 1

As it stands now, flextable does not allow duplicate column keys. However, you can achieve the same result by adding a row of "headers," or a row of column labels, to the top of your table. These headers can contain duplicate values.
You do this with the "add_header_row" function.
Here is a base example using the iris data set.
ft <- add_header_row(
ft,
values = c("", "length", "width", "length", "width"),
top = FALSE
)
ft <- theme_box(ft)
https://davidgohel.github.io/flextable/articles/layout.html

Answer 2

I found a work around by adding the character \r to the column names to create unique column names :
library(flextable)
A <- matrix(rnorm(8), nrow = 2, ncol = 4)
A <- as.data.frame(A)
col_Names <- c("a","b","a","b")
nb_Col_Names <- length(col_Names)
for(i in 1 : nb_Col_Names)
{
col_Names[i] <- paste0(col_Names[i], paste0(rep("\r", i), collapse = ""), collapse = "")
}
colnames(A) <- col_Names
tbl_A <- flextable(A)

Answer 3

Currently, using set_header_labels:
library(flextable)
a<-c(1:8)
b<-c(1:8)
c<-c(2:9)
d<-c(2:9)
A <- data.frame(a,b,c,d)
flextable(A) |> set_header_labels(`a` = "a", `b` = "b", `c` = "a", `d` = "b")