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The levels a categorical column is plotted in, optionally reordered

Source: R/level_order.R
level_order_choices.Rd

Gives the levels of data[[column]] that are present, in the order a plot draws them by default - factor level order for a factor, sorted values otherwise - with any levels named in order moved to the front in that order.

Usage

level_order_choices(data, column, order = NULL, max.levels = 20)

Arguments

data

A data frame.

column

The name of the column.

order

Optional character vector of levels in the order wanted. Entries that are not present levels are ignored, and levels it leaves out follow in their default order, so an order kept from an earlier filtering of the data still applies to what is left.

max.levels

The most levels worth offering for reordering. A column with more gives NULL.

Value

A character vector of levels, or NULL when column is missing, numeric, or has no levels or more than max.levels of them.

See also

level_order_input(), apply_level_order(), setup_level_order()

Author

Jared Andrews

Examples

level_order_choices(example_iris, "Species")
#> [1] "setosa"     "versicolor" "virginica" 
level_order_choices(example_iris, "Species", order = "virginica")
#> [1] "virginica"  "setosa"     "versicolor"

# Numeric columns have no levels to order
level_order_choices(example_iris, "Sepal.Length")
#> NULL