CODEWITHSUNDEEP
rplotggplot2
neversaint
neversaint

Reputation: 63984

How to do selective labeling with GGPLOT geom_point()

With this code:

library(ggplot2)
p <- ggplot(mtcars, aes(wt, mpg))
p + geom_point()
p + geom_point() + geom_text(aes(wt, mpg, label=row.names(mtcars)))

I obtain this graph:

enter image description here

How can I modify the code above so that it only labels point where wt > 4 or mpg > 25, while the rest of the points remain unlabeled.

Upvotes: 41

Views: 93418

Answers (5)

ElizabethPermina1947140
ElizabethPermina1947140

Reputation: 67

library(ggrepel)

mtcars$name <- row.names(mtcars)

ggplot(mtcars, aes(wt, mpg, label=name)) +

geom_point() +

geom_text_repel(data=subset(mtcars, wt > 4 | mpg > 25), aes(label=name))

Upvotes: 2

agstudy
agstudy

Reputation: 121568

a ggplot2-like lattice solution :-)

  library(latticeExtra)
  xyplot(mpg~wt, data=mtcars,pch=19,
         panel =function(x,y,...){
         #  panel.xyplot(x,y,...)
           data=subset(mtcars, wt > 4 | mpg > 25)
           panel.text(data$wt,data$mpg,label=row.names(data),
                      col='red',cex=2)
         },par.settings = ggplot2like(), axis = axis.grid)

enter image description here

Upvotes: 3

Marius
Marius

Reputation: 60060

Supply a data argument to geom_text:

library(ggplot2)
mtcars$name <- row.names(mtcars)
p <- ggplot(mtcars, aes(wt, mpg))
p + geom_point()
p + geom_point() + 
  geom_text(data=subset(mtcars, wt > 4 | mpg > 25),
            aes(wt,mpg,label=name))

Resulting plot:

plot1

PS: I'm really not a fan of the p + geom() style of constructing ggplots, I'm pretty sure hadley did it in the original ggplot2 book to demonstrate different modifications of the same plot, but people seem to have picked it up and run with it. Here's how I'd do it:

  • Just add the different components of the plot together with +, don't save each intermediate step.
  • Don't bother saving it to a variable unless you really need to, you can still save it to a file if you need to with ggsave()
  • Put all the aesthetics that are going to apply to the whole plot in the first ggplot call, only modify the other things if necessary

My version:

ggplot(mtcars, aes(wt, mpg, label=name)) +
  geom_point() +
  geom_text(data=subset(mtcars, wt > 4 | mpg > 25))

Upvotes: 90

sebastian-c
sebastian-c

Reputation: 15395

You could just get an extra variable:

carnames <- row.names(mtcars)
carnames[with(mtcars, !(wt > 4 | mpg > 25))] <- ""

p + geom_point() + geom_text(aes(wt,mpg,label=carnames))

Upvotes: 3

mnel
mnel

Reputation: 115382

You can pass a subset argument to a layer. In your case this would require having the rownames as a column, so they are evaluated properly. You will need to explicitly load plyr to get the function . which makes the syntax easy.

# shamelessly using @marius initial code
library(ggplot2)
library(plyr)
mtcars$name <- row.names(mtcars)
p <- ggplot(mtcars, aes(wt, mpg))

p + geom_point() + geom_text(aes(wt,mpg,label=name), subset = .(wt > 4 | mpg > 25))

Upvotes: 6

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