scale_x_grates_period: Period scale

In grates: Grouped Date Classes

Period scale

Description

ggplot2 scale for an ⁠<grates_period>⁠ vector.

Usage

scale_x_grates_period(
  ...,
  breaks = ggplot2::waiver(),
  n.breaks = 6L,
  format = "%Y-%m-%d",
  n,
  offset
)

Arguments

...	Not currently used.
breaks	A ⁠<grates_period>⁠ vector of the desired breaks.
n.breaks	⁠[integer]⁠ Approximate number of breaks calculated using scales::breaks_pretty (default 6L). Will only have an effect if breaks = waiver().
format	Format to use for dates. Value is used by format.Date() and can be any input acceptable by that function.
n	⁠[integer]⁠ Number of days in each period.
offset	⁠[integer]⁠ Number of days used in original grouping for the offset from the Unix Epoch.

Value

A scale for use with ggplot2.

Examples

# use simulated linelist data from the outbreaks package
linelist <- outbreaks::ebola_sim_clean$linelist

# Calculate the total of infections across 14 day periods offset from
# the first date
x <- linelist$date_of_infection
x <- as_period(x, n = 14, offset = min(x, na.rm = TRUE))
dat <- aggregate(list(cases = x), by = list(period = x), FUN = length)
head(dat)

(period_plot <- ggplot2::ggplot(dat, ggplot2::aes(period, cases)) +
    ggplot2::geom_col(width = 1, colour = "white") +
    ggplot2::theme_bw() +
    ggplot2::theme(
        axis.text.x = ggplot2::element_text(
            angle = 45,
            hjust = 1
        )
    ) +
    ggplot2::xlab(""))

# To change defaults we must explicitly state the value of n and
# offset when calling the scale function
period_plot + scale_x_grates_period(
    n.breaks = 2,
    n = 14,
    offset = min(x, na.rm = TRUE)
)

grates documentation built on April 3, 2025, 10:49 p.m.