r - Unicode with knitr and Rmarkdown

Question

Is there a set of best practices or documentation for working with Unicode in knitr and Rmarkdown? I can't seem to get any glyphs to show up properly when knitting a document.

For example, this works in the console (in Rstudio):

> cat("U2660   U2665  U2666  U2663")
?   ?   ?   ?

But when knitting I get this:

• HTML
• Word

(Cloud services are blocked for me, so I can't upload images directly to SO).

Answer 1

It looks like an encoding issue specific to Windows, and may be related to this issue: https://github.com/hadley/evaluate/issues/59 Unfortunately we have to wait for a fix in base R, but if you don't have to use cat(), and this expression is a top-level expression in your code chunk (e.g. not inside a for-loop or if-statement), I guess this may work:

knitr::asis_output("U2660   U2665  U2666  U2663")

It passes the character string directly to knitr and bypasses cat(), since knitr cannot reliably catch multibyte characters written out by cat() on Windows -- it depends on whether the characters can be represented by your system's native encoding.