Does a plot or layer use the correct data set?

uses_data checks whether the data set used by a plot or layer matches the data set provided.

Usage

uses_data(p, data, local_only = FALSE)

Arguments

p

A ggplot object or a layer extracted from a ggplot object with get_geom_layer.

data

A data frame

local_only

TRUE or FALSE. See the details.

Value

A data frame.

Details

When passed a ggplot object (i.e. a plot), uses_data will check only the data that has been set globally with ggplot.

When passed a single layer from a plot, the behavior of uses_data will depend on the local_only argument passed to .... If local_only = TRUE, uses_data will check only the data set, if any, that was defined locally in the function that created the layer. If local_only = FALSE, uses_data will check the data used by the layer, whether or not that data was defined globally in ggplot or locally.

See also

Other functions for checking data: get_data(), ith_data_is(), ith_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()
uses_data(p, mpg)
#> [1] TRUE
uses_data(get_geom_layer(p, i = 1), data = head(mpg))
#> [1] TRUE