How can I produce more than one file format per plot code in R?

Question

I use Github markdown to document my data analysis with R. When I make a plot I use:

jpeg("file_name.jpg")
plot(...)
dev.off()

to save the plot as a jpeg that can then be embedded and displayed in the markdown document like this:

!(file_name.jpg)

However, I also need to make a pdf of the plot for the final publication. Currently I write the entire plot code over again with pdf("file_name.pdf") but this results in a lot of basically duplicate code.

I have tried putting the jpeg and pdf calls in sequence but then only the bottom one gets produced.

Is there a way to make the jpeg and pdf file from the same code during only one run of the code?

Answer 1

Or you can use dev.copy:

plot(cars)
dev.copy(jpeg, "cars.jpeg")
dev.off()
dev.copy(pdf, "cars.pdf")
dev.off()

Answer 2

Why not to use knitr? for example:

```{r myplot,fig.width=7, fig.height=6,dev=c('png','pdf','jpeg')}
plot(cars)
```

This will create 3 versions/files of the same plot:

1. myplot.png
2. myplot.jpeg
3. myplot.pdf