`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.

`reorder(x, …)`# S3 method for default
reorder(x, X, FUN = mean, …,
order = is.ordered(x))

x

an atomic vector, usually a `factor`

(possibly
ordered). The vector is treated as a categorical variable whose
levels will be reordered. If `x`

is 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 of `x`

determines the
eventual order of that level.

FUN

a `function`

whose first argument is a vector
and returns a scalar, to be applied to each subset of `X`

determined by the levels of `x`

.

…

optional: extra arguments supplied to `FUN`

order

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
`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.

This, as `relevel()`

, is a special case of simply calling
`factor(x, levels = levels(x)[....])`

.

# 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") # }

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