Backport of .valid.factor for R < 3.4.0

Source: R/valid.factor.R

See the original description in base::.valid.factor.

.valid.factor(object)

Examples

# get function from namespace instead of possibly getting
# implementation shipped with recent R versions:
bp_.valid_factor = getFromNamespace(".valid.factor", "backports")
bp_.valid_factor(factor(letters[1:3]))
#> [1] TRUE