Thanks to the many! people who answered my query about removing columns
from a data frame. (I couldn't track that down in the splus help
system, nor using the indices of a couple of books.)
I'll provide just a few responses, as they cover the gamut:
Bill Venables:
You can do it the same way that you remove columns from a matrix:
Suppose you want to remove columns 2, 3 & 4:
Dat <- Dat[, -(2:4)] # comma and parens necessary...
You can also remove individual columns by name the same way as you would
remove components from a list
Dat$c2 <- Dat$c3 <- Dat$c4 <- NULL.
Cheryl Howard (using the gui):
Select the column; Under the Data menu item, select Remove submenu, then
select column. A dialog will appear to verify which column to remove.
Even easier, but perhaps less obvious, in the second line of the tool
bar (when you have a data frame open) you'll see an icon that in three
light grey bars with a black bar with a down arrow. This removes the
selected column.
Nick Ellis:
By name?
dat <- dat[,-match("b",names(dat))]
to remove column with name "b".
Multiple columns?
dat <- dat[,-c(3,6)]
dat <- dat[,-match(c("b","g"),names(dat))]
Again, thanks to everyone else too.
Dave Parkhurst
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