CODEWITHSUNDEEP
rggplot2facet
Thomas Speidel
Thomas Speidel

Reputation: 1443

ggplot with facets and geom_abline

Suppose I have data like these:

n <- 100
set.seed(123)    
df <- data.frame(
    num1 = rnorm(n),
    num2 = sample(1:4, n, replace = TRUE),
    char = sample(c("Green", "Red", "Blue"), n, replace = TRUE),
    fac  = factor(sample(c("Green", "Red", "Blue"), n, replace = TRUE)),
    logical = sample(c(TRUE, FALSE), n, replace = TRUE),
    stringsAsFactors = FALSE
)

I'd like to generate a ggplot with facets and reference lines so that the reference lines are plotted in the appropriate facet. For instance:

## Base plot
ggplot(df, aes(num2, num1)) + 
geom_jitter() + 
facet_grid(~ char)

enter image description here

Now I'd like to add vertical lines whenever logical == TRUE.

enter image description here

Something like:

## Does not work
ggplot(df, aes(num2, num1)) + 
geom_jitter() + 
facet_grid(~ char) +
geom_vline(xintercept = num2)

Upvotes: 1

Views: 390

Answers (1)

Nate
Nate

Reputation: 10671

You need to map your xintercept value inside of aes(), to tell ggplot to look inside of data for it. And subset the data for just that layer, based on your conditional.

ggplot(df, aes(num2, num1)) + 
    geom_jitter() + 
    facet_grid(~ char) +
    geom_vline(data = df[df$logical == TRUE,], aes(xintercept = num2))

enter image description here

Upvotes: 2

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