Conditional slides in R markdown (beamer presentation)

问题

Is it possible to have conditional slides in R markdown (beamer presentation)? I tried using R code chunk hacks with results = 'asis' and further tried using custom LaTeX commands but to no avail. One problem seems to be that each markdown slide delimiter actually results in the combination of both

\end{frame}
\begin{frame}

so it is hard to conditionally exclude a slide.

来源：https://stackoverflow.com/questions/43396667/conditional-slides-in-r-markdown-beamer-presentation