Is it possible to reorder columns in a data frame so that initial order ABCDE is reordered to ABDCE by specifying that you want to move column D from its current location to between B and C?
For example, the mtcars dataset has the current order below:
mtcars <- data.frame(mtcars)
> colnames(mtcars)
[1] "mpg" "cyl" "disp" "hp" "drat" "wt" "qsec" "vs" "am" "gear" "carb"
I want to move the column gear to a position between disp and hp by running code that specifically asks to move "gear" to a position between disp and hp. The result would like like below, in the data frame mtcars_reordered.
> colnames(mtcars_reordered)
[1] "mpg" "cyl" "disp" "gear" "hp" "drat" "wt" "qsec" "vs" "am" "carb"
This would make it easier to reorder data frames without specifying the order of all variables.
Is this possible? If so, how would it be done?
Try the following function.
Argument swap is the names of the 3 columns before reordering them.
reorder_df_cols <- function(x, swap){
i_swap <- match(swap, names(x))
tmp1 <- x[seq_len(i_swap[1])]
vars <- x[rev(i_swap[-1])]
tmp2 <- x[-c(seq_len(i_swap[1]), i_swap[-1])]
cbind(tmp1, vars, tmp2)
}
data(mtcars, package = "datasets")
swap <- c("disp", "hp", "gear")
colnames(reorder_df_cols(mtcars, swap))
# [1] "mpg" "cyl" "disp" "gear" "hp" "drat" "wt" "qsec" "vs"
#[10] "am" "carb"