R, how to add one break to the default breaks in ggplot?

Question

Suppose I have the following issue: having a set of data, generate a chart indicating how many datapoints are below any given threshold.

This is fairly easy to achieve

n.data <- 215 set.seed(0) dt <- rnorm(n.data) ** 2 x <- seq(0, 5, by=.2) y <- sapply(x, function(i) length(which(dt < i))) ggplot() + geom_point(aes(x=x,y=y)) + geom_hline(yintercept = n.data)

The question is, suppose I want to add a label to indicate what the total number of observation was (n.data). How do I do that, while maintaining the other breaks as default?

The outcome I'd like looks something like the image below, generated with the code

ggplot() + geom_point(aes(x=x,y=y)) + geom_hline(yintercept = n.data) + scale_y_continuous(breaks = c(seq(0,200,50),n.data))

However, I'd like this to work even when I change the value of n.data, just by adding it to the default breaks. (bonus points if you also get rid of the grid line between the last default break and the n.data one!)

Did you manage to get this done? (Not a duplicate at all BTW) — Dan Chaltiel
– Dan Chaltiel, Commented Apr 21, 2021 at 10:55
@DanChaltiel, thanks for reopening this. I've added an answer about how I would approach this today. — ltr
– ltr, Commented Apr 27, 2021 at 4:05

ltr · Accepted Answer · 2021-04-27 04:05:01Z

6

Three years and some more knowledge of ggplot later, here's how I would do this today.

ggplot() + geom_point(aes(x=x,y=y)) + geom_hline(yintercept = n.data) + scale_y_continuous(breaks = c(pretty(y), n.data))

answered Apr 27, 2021 at 4:05

ltr

3603 silver badges10 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Paul Schmidt Over a year ago

Thanks. Based on this I made it work for a more general case, where n.data is not necessarily the last value, via sort(unique(c(my_values, pretty(y))))

John-Henry Over a year ago

@PaulSchmidt I don't think you need to do this? Worked fine for me without sorting, but I also didn't have duplicate values.

Boidot · Accepted Answer · 2017-11-20 13:21:16Z

Here is how you can get rid of the grid line between the last auto break and the manual one :

theme_update(panel.grid.minor=element_blank())

For the rest, I can't quite understand your question, as when you change n.data, your break is updated.

Collectives™ on Stack Overflow

R, how to add one break to the default breaks in ggplot?

2 Answers 2

2 Comments

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Linked

Related