Add a prefix to column names

Solution 1:

You have misread the help file. Here's the argument to look at:

do.NULL: logical. If FALSE and names are NULL, names are created.

Notice the and in that description. Your names are no longer NULL, so using prefix won't work.

Instead, use something like this:

> m2 <- cbind(1,1:4)
> colnames(m2) <- c("x","Y")
> colnames(m2) <- paste("Sub", colnames(m2), sep = "_")
> m2
     Sub_x Sub_Y
[1,]     1     1
[2,]     1     2
[3,]     1     3
[4,]     1     4

Solution 2:

I will add a tidyverse approach to this problem, for which you can both add suffix and prefix to all column names. The following adds a prefix in a dplyr pipe.

dplyr 1.0.2 and beyond

library(dplyr)
df <- data.frame(x = c(1, 2), y = c(3, 4))

## Adding prefixes
df %>% rename_with( ~ paste0("a", .x))

## Adding suffixes
df %>% rename_with( ~ paste0(.x, "a"))

If you want to have separators such as underline, you can use paste as well with the sep argument.

Before dplyr 1.0.2 update

library(dplyr)
df <- data.frame(x = c(1, 2), y = c(3, 4))
df %>% rename_all( ~ paste0("a", .x))

Adding suffix is easier.

df %>% rename_all(paste0, "a")

Solution 3:

The updated tidyverse method (with dplyr 1.0.2) uses rename_with() as the rename_all() function has been superseded.

iris %>% rename_with( ~ paste("Sub", .x, sep = "_"))