Dynamic Documents with R and knitr, 2nd Edition

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Cross Reference

We can cross reference both code chunks and child documents in knitr. This enables us to better organize our source documents. Below is a practical example: we have a custom ggplot2 theme and we want to apply it to a few plots in the document.

If we were to use this piece of code only once, we can just copy and paste it to the code chunk, but it is certainly not a good idea to paste it to multiple chunks, since it will be a disaster to maintain. We can simply use a reference to it using its chunk label, e.g.,

Then knitr will ...