3 ms·
Erm ... Well, I admit it's somewhat confusing. factor(x = character(), levels, labels = levels, exclude = NA, ordered = is.ordered(x), nmax = NA) [...
by stewbrew 9y ago
Erm ... Well, I admit it's somewhat confusing.
factor(x = character(), levels, labels = levels, exclude = NA, ordered = is.ordered(x), nmax = NA)
[...]
levels
: an optional vector of the values (as character strings) that x might
have taken. The default is the unique set of values taken by
as.character(x), sorted into increasing order of x. Note that this set
can be specified as smaller than sort(unique(x)).
labels
: either an optional character vector of (unique) labels for the
levels (in the same order as levels after removing those in exclude), or
a character string of length 1.
This way, you can do something like that:
> x <- 1:3
> factor(x, levels = 1:2, labels = c("foo", "bar"))
[1] foo bar <NA>
Levels: foo bar
But this actually is:
> factor(as.character(x), levels = c("1", "2"), labels = c("foo", "bar"))
[1] foo bar <NA>
Levels: foo bar