This help topic is for R version 0.60. For the current version of R, try https://stat.ethz.ch/R-manual/R-patched/library/base/html/nlevels.html
nlevels {base}R Documentation

The Number of Levels of a Factor

Description

nlevels returns the number of levels which its argument has. If the argument is not a factor NA is returned.

The actual factor levels (if they exist) can be obtained with the levels function.

Usage

nlevels(x)

See Also

levels.

[Package base version 0.60 ]