Drop data frame columns by name

Question

I have a number of columns that I would like to remove from a data frame. I know that we can delete them individually using something like:

df$x <- NULL
<         


        

Answer 1

Another possibility:

df <- df[, setdiff(names(df), c("a", "c"))]

or

df <- df[, grep('^(a|c)$', names(df), invert=TRUE)]

Answer 2

Another solution if you don't want to use @hadley's above: If "COLUMN_NAME" is the name of the column you want to drop:

df[,-which(names(df) == "COLUMN_NAME")]