Does the ith layer use the correct data set?

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.

Value

TRUE or FALSE

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.

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)
#> [1] TRUE