15 Scales and guides
15.1 Exercises
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# ggplot(mpg, aes(displ)) +
# scale_y_continuous("Highway mpg") +
# scale_x_continuous() +
# geom_point(aes(y = hwy))
# The above can be modified to:
# mpg %>%
# ggplot(aes(displ, hwy)) +
# geom_point() +
# labs(y = "Highway mpg")
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# ggplot(mpg, aes(y = displ, x = class)) +
# scale_y_continuous("Displacement (l)") +
# scale_x_discrete("Car type") +
# scale_x_discrete("Type of car") +
# scale_colour_discrete() +
# geom_point(aes(colour = drv)) +
# scale_colour_discrete("Drive\ntrain")
# The above can be modified to
# mpg %>%
# ggplot(aes(class, displ)) +
# geom_point(aes(color = drv)) +
# labs(x = "Type of car",
# y = "Displacement (l)",
# color = "Drive\ntrain")
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####################################2. What happens if you pair a discrete variable with a continuous scale? What happens if you pair a continuous variable with a discrete scale?
mpg %>%
ggplot(aes(class, displ)) +
geom_point(aes(color = drv)) +
scale_y_discrete() +
labs(x = "Type of car",
y = "Displacement (l)",
color = "Drive\ntrain")
When you pair a discrete variable with a continuous scale, you don’t see a plot and get this error message: Discrete value supplied to continuous scale
When you pair a continuous variable with a discrete scale, as seen above, you get a different looking plot that doesn’t contain the proper axis ticks or grid lines.