What is this knitr magic that produces a plot by calling <<plot_this>>?
问题 I am trying to work out how this report on a STAN model for the 2016 US presidential elections is generated using rmarkdown : https://raw.githubusercontent.com/pkremp/polls/master/report.Rmd I have looked at the source code available on github, which contains lines like: # Electoral College ```{r echo=FALSE, message=FALSE, fig.align='center'} <<plot_ev>> ``` The command <<plot_ev>> seems to generate plots from code in graphs.R: # Not accounting for the EV allocation rules of Nebraska and