The levels of a factor are re-ordered so that the level specified by ref is
first and the others are moved down. This is a copy from relevel
in the stats package, but preserves the label
attribute and class papaja_labelled
.
# S3 method for papaja_labelled
relevel(x, ref, ...)
an unordered factor.
the reference level, typically a string.
additional arguments for future methods.