Drop data frame columns by name

You can use a simple list of names :

DF <- data.frame(  x=1:10,  y=10:1,  z=rep(5,10),  a=11:20)drops <- c("x","z")DF[ , !(names(DF) %in% drops)]

Or, alternatively, you can make a list of those to keep and refer to them by name :

keeps <- c("y", "a")DF[keeps]

EDIT :For those still not acquainted with the drop argument of the indexing function, if you want to keep one column as a data frame, you do:

keeps <- "y"DF[ , keeps, drop = FALSE]

drop=TRUE (or not mentioning it) will drop unnecessary dimensions, and hence return a vector with the values of column y.

There's also the subset command, useful if you know which columns you want:

df <- data.frame(a = 1:10, b = 2:11, c = 3:12)df <- subset(df, select = c(a, c))

UPDATED after comment by @hadley: To drop columns a,c you could do:

df <- subset(df, select = -c(a, c))

within(df, rm(x))

is probably easiest, or for multiple variables:

within(df, rm(x, y))

Or if you're dealing with data.tables (per How do you delete a column by name in data.table?):

dt[, x := NULL]   # Deletes column x by reference instantly.dt[, !"x"]   # Selects all but x into a new data.table.

or for multiple variables

dt[, c("x","y") := NULL]dt[, !c("x", "y")]