Fix error message for geom_density() when using y

[Maschette]

Hi,
The error message for geom_density() when using x and y comes up and says y is missing. My suggestion would be to change the error when x and y are present but stat is not identity to "y is present, did you mean to use stat = 'identity'" or something like that. Also adding an example that uses x and y to https://ggplot2.tidyverse.org/reference/geom_density.html would be great.

x<-data.frame(value=seq(0,1,by=0.2), count=rnorm(6, mean = 10) )

library(ggplot2)
#> Warning: package 'ggplot2' was built under R version 3.6.1

ggplot(x)+geom_density(aes(x=value, y=count))
#> Error: geom_density requires the following missing aesthetics: y

ggplot(x)+geom_density(aes(x=value, y=count), stat = 'identity')

^{Created on 2019-09-02 by the reprex package (v0.3.0)}

[batpigandme]

Hi Dale,
Would you want to do a PR for this?

[Maschette]

Hi Mara,
If i knew how I might. I find tracking of error messages in ggplot really hard so I might leave it to someone else.

Thanks for asking though.

[batpigandme]

Completely understood!

[yutannihilation]

I agree about the error message, but I don't feel it's nice to use geom_density() without stat_density(). Maybe you should use geom_area()?

[carywreams]

Question 1

Should this have been closed as indicated in #3519 ?

Question 2

Looks like a check for/warning of 'supplied x and y but specified stat="density" by default') could be applied in R/geom-density.r during the GeomDensity call to ggplot.

Right track ?

I'll be looking through other geom- source for similar compatibility checks.

My Notes

• where.log

[stragu]

@thomasp85 , sorry if I misunderstood this, but it seems the issue as described by @Maschette is still the same in ggplot2 3.3.2:

x <- data.frame(value = seq(0, 1, by = 0.2),
                count = rnorm(6, mean = 10))
library(ggplot2)
ggplot(x) +
  geom_density(aes(x = value, y = count))
#> Error: geom_density requires the following missing aesthetics: y

^{Created on 2020-08-10 by the reprex package (v0.3.0)}

[chasemc]

Same for v3.3.5

[francisbarton]

@Maschette this helped me solve the error message, when nothing else on the internet did. Thank you.