ith_data_is: Does the ith layer use the correct data set?

In rstudio-education/ggcheck: Inspect 'ggplot2' Plots for Automated Grading in Learning Exercises

Does the ith layer use the correct data set?

Description

ith_data_is checks whether the student uses the supplied data set for the ith layer of their plot.

Usage

ith_data_is(p, data, i, local_only = FALSE)

Arguments

p	A ggplot object or a layer extracted from a ggplot object with get_geom_layer.
data	A data frame
i	A numerical index that corresponds to the first layer of a plot (1), the second layer (2), and so on.
local_only	TRUE or FALSE. See the details.

Details

Functions that use the ith_ prefix are designed to eliminate the need to call get_geom_layer to check a specific layer in a plot, e.g. p %>% get_geom_layer(geom = "point") %>% uses_data(mpg).

If local_only = TRUE, ith_data_is will check only the data set, if any, that was defined locally in the function that created the ith layer. If local_only = FALSE, ith_data_is will check the data used by the ith layer, whether or not that data was defined globally in ggplot or locally.

Value

TRUE or FALSE

See Also

Other functions for checking data: get_data(), ith_data(), uses_data()

Examples

require(ggplot2)
d2 <- head(mpg)
p <- ggplot(data = mpg, mapping = aes(x = displ, y = hwy)) +
  geom_point(data = d2, color = "red") +
  geom_point()
ith_data_is(p, data = head(mpg), i = 1)

rstudio-education/ggcheck documentation built on May 12, 2023, 11:33 a.m.