reorder.default
Reorder Levels of a Factor
reorder is a generic function. The "default" method
treats its first argument as a categorical variable, and reorders its
levels based on the values of a second variable, usually numeric.
- Keywords
- utilities
Usage
reorder(x, …)# S3 method for default
reorder(x, X, FUN = mean, …,
order = is.ordered(x))
Arguments
- x
an atomic vector, usually a
factor(possibly ordered). The vector is treated as a categorical variable whose levels will be reordered. Ifxis not a factor, its unique values will be used as the implicit levels.- X
a vector of the same length as
x, whose subset of values for each unique level ofxdetermines the eventual order of that level.- FUN
a
functionwhose first argument is a vector and returns a scalar, to be applied to each subset ofXdetermined by the levels ofx.- …
optional: extra arguments supplied to
FUN- order
logical, whether return value will be an ordered factor rather than a factor.
Details
This, as relevel(), is a special case of simply calling
factor(x, levels = levels(x)[....]).
Value
A factor or an ordered factor (depending on the value of
order), with the order of the levels determined by
FUN applied to X grouped by x. The
levels are ordered such that the values returned by FUN
are in increasing order. Empty levels will be dropped.
Additionally, the values of FUN applied to the subsets of
X (in the original order of the levels of x) is returned
as the "scores" attribute.
See Also
Examples
library(stats)
# NOT RUN {
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")
# }