R ggplot2 as_labeller 强制贴标机函数

as_labeller(x, default = label_value, multi_line = TRUE)

labeller()、labellers

p <- ggplot(mtcars, aes(disp, drat)) + geom_point()
p + facet_wrap(~am)


# Rename labels on the fly with a lookup character vector
to_string <- as_labeller(c(`0` = "Zero", `1` = "One"))
p + facet_wrap(~am, labeller = to_string)


# Quickly transform a function operating on character vectors to a
# labeller function:
appender <- function(string, suffix = "-foo") paste0(string, suffix)
p + facet_wrap(~am, labeller = as_labeller(appender))


# If you have more than one faceting variable, be sure to dispatch
# your labeller to the right variable with labeller()
p + facet_grid(cyl ~ am, labeller = labeller(am = to_string))