Reorder Levels of a Factor
reorder is a generic function. The
treats its first argument as a categorical variable, and reorders its
levels based on the values of a second variable, usually numeric.
## S3 method for class 'default': reorder(x, X, FUN = mean, \dots, order = is.ordered(x))
- An atomic vector, usually a factor (possibly ordered). The vector
is treated as a categorical variable whose levels will be reordered.
xis not a factor, its unique values will be used as the implicit levels.
- a vector of the same length as
x, whose subset of values for each unique level of
xdetermines the eventual order of that level.
- a function whose first argument is a vector and
returns a scalar, to be applied to each subset of
Xdetermined by the levels of
- optional: extra arguments supplied to
- logical, whether return value will be an ordered factor rather than a factor.
- A factor or an ordered factor (depending on the value of
order), with the order of the levels determined by
x. The levels are ordered such that the values returned by
FUNare in increasing order. Empty levels will be dropped.
Additionally, the values of
FUNapplied to the subsets of
X(in the original order of the levels of
x) is returned as the
require(graphics) bymedian <- with(InsectSprays, reorder(spray, count, median)) boxplot(count ~ bymedian, data = InsectSprays, xlab = "Type of spray", ylab = "Insect count", main = "InsectSprays data", varwidth = TRUE, col = "lightgray")