How can I format axis labels with exponents with ggplot2 and scales?

Question

With the new version ggplot2 and scales, I can\'t figure out how to get axis label in scientific notation. For example:

x <- 1:4
y <- c(0, 0.0001, 0.00         


        

Answer 1

Riffing off of Tom's answer above, the following removes + signs, and handles 0 better (the function is anonymously inlined as well):

scale_y_continuous(label= function(x) {ifelse(x==0, "0", parse(text=gsub("[+]", "", gsub("e", " %*% 10^", scientific_format()(x)))))} ) +

Answer 2

I adapted Brian's answer and I think I got what you're after.

Simply by adding a parse() to the scientific_10() function (and changing 'x' to the correct 'times' symbol), you end up with this:

x <- 1:4
y <- c(0, 0.0001, 0.0002, 0.0003)

dd <- data.frame(x, y)

scientific_10 <- function(x) {
  parse(text=gsub("e", " %*% 10^", scales::scientific_format()(x)))
}

ggplot(dd, aes(x, y)) + geom_point()+scale_y_continuous(label=scientific_10)

You might still want to smarten up the function so it deals with 0 a little more elegantly, but I think that's it!

Answer 3

I wrote a version of scientific_10 that avoids the scales package; it also removes leading zeroes in exponents (10^04 to 10^4, etc.). This was adapted from the helpful answers given above.

I've also included wrapper scale functions below.

scientific_10 <- function(x) {
    xout <- gsub("1e", "10^{", format(x),fixed=TRUE)
    xout <- gsub("{-0", "{-", xout,fixed=TRUE)
    xout <- gsub("{+", "{", xout,fixed=TRUE)
    xout <- gsub("{0", "{", xout,fixed=TRUE)
    xout <- paste(xout,"}",sep="")
    return(parse(text=xout))
}

scale_x_log10nice <- function(name=NULL,omag=seq(-10,20),...) {
    breaks10 <- 10^omag
    scale_x_log10(name,breaks=breaks10,labels=scientific_10(breaks10),...)
}

scale_y_log10nice <- function(name=NULL,omag=seq(-10,20),...) {
    breaks10 <- 10^omag
    scale_y_log10(name,breaks=breaks10,labels=scientific_10(breaks10),...)
}

scale_loglog <- function(...) {
    list(scale_x_log10nice(...),scale_y_log10nice(...))
}

qplot(x=exp(5*rnorm(100)),geom="density",kernel="rectangular") + 
    scale_x_log10nice()

Answer 4

scale_y_continuous(label=scientific_format())

gives labels with e instead of 10:

I suppose if you really want 10's in there, you could then wrap that in another function.

scientific_10 <- function(x) {
  gsub("e", " x 10^", scientific_format()(x))
}

ggplot(dd, aes(x, y)) + geom_point() + 
  scale_y_continuous(label=scientific_10)

Answer 5

As per the comments on the accepted solution, OP is looking to format exponents as exponents. This can be done with the trans_format and trans_breaks functions in the scales package:

    library(ggplot2)
    library(scales)

    x <- 1:4
    y <- c(0, 0.0001, 0.0002, 0.0003)
    dd <- data.frame(x, y)

    ggplot(dd, aes(x, y)) + geom_point() +
    scale_y_log10("y",
        breaks = trans_breaks("log10", function(x) 10^x),
        labels = trans_format("log10", math_format(10^.x)))