在刻面上添加不同的垂直线 ggplot2

Question

I am quite a newbie to RStudio and I am having problems adding different vertical lines on each of my two facets using facet_wrap

Here is what I thought:

library(ggplot2)

g <- ggplot(dat, aes(x=index, na.rm= TRUE))

d <- g+ geom_density() + facet_wrap(~gender)

vline.data <- data.frame(z = c(2.36,2.48),gender = c("Female","Male")) 

d1 <- d + geom_vline(aes(xintercept = z),vline.data)

But it adds the same two lines to each facet - what would you reckon is the problem? I have thought of somehow splitting the facets into two separate data frames, but I have no idea how to go on about it.

PS The x-axis (the index) goes from 1 to 4.

Thank you in advance.

        index  <-  c(NA, NA, 4, 4, 4, NA, NA, NA, NA, 2, 2, 2, 2, 2, 3, 3, 3, 3, 
        3, NA, 3, NA, NA, 3, 4, 4, 4, 4, 4, 3, 4, 3, 4, 3, NA, 4, 2, 
        4, 4, 2, 2, NA, 2, 3, 3, 2, 2, NA, NA, 2)

       gender <-  c("Female", "Female", "Male", "Male", "Male", "Female", "Female", 
        "Male", "Female", "Male", "Female", "Male", "Female", "Male", 
        "Male", "Female", "Female", "Female", "Male", "Female", "Female", 
        "Male", "Male", "Female", "Female", "Female", "Male", "Male", 
        "Female", "Female", "Male", "Female", "Female", "Female", "Male", 
        "Male", "Female", "Male", "Male", "Female", "Female", "Male", 
        "Male", "Female", "Female", "Male", "Male", "Male", "Male", "Male")

Using the code and data above I get this plot

Answer 1

This was asked a long time ago, but here's the answer:

You need to add geom_vline to your ggplot. geom_vline takes a single value, not a vector, and it doesn't iterate, so you can't have multiple values in a separate data object from the rest of your data. Merge vline.data as a new column with the rest of dat as is appropriate for your data set. This question doesn't have reproducible data, but put index , gender and however you calculate vline.data into a single dat dataframe with each of those pieces as column names. Then you can summarise the vline.data . The example below assumes the values within vline.data are the mean values for the entire index column.

p <- ggplot(dat, aes(x=index, na.rm= TRUE)) +
  geom_density() + 
  facet_wrap(. ~ gender) +
  geom_vline(data = . %>% group_by(gender) %>% summarise(vl=mean(index)), 
             aes(xintercept=vl))

How to Add Lines With A Facet R