[texhax] include a pdf graphics file whose name includes a varying date

[Christopher W Ryan]

I am using R and Sweave and MikTeX on Windows 7.  I use this workflow
to generate a recurring report quarterly. Same report, just new data.

The R code generates a graph, saving it as a pdf file, the filename
including the date.  Each time I run the report, I want to include the
most current graph. How would I do that?

Example code (just excerpts, does not actually compile, but I think it
will convey my intent):

<<timeseriesplot, results=hide, echo=FALSE>>=
# make the major graph
pdf(file=paste("NaloxoneUseEMS-timeseriesplot-", Sys.Date(), ".pdf",
sep=""), height=8, width=12)
## bunch of R code in here to create a graph
dev.off()
@


The later in the file, I have:

\begin{figure}\centering
  \includegraphics{NaloxoneUseEMS-timeseriesplot-2016-08-04}
\end{figure}
 ^^^^^^^^^^^^^

     here is the problem

     How do I make this

     part of the figure filename

     increment to match SysDate()

     from R in the code chunk above?


I understand I could just include the code-generating chunk inside a
Sweave environment with fig=TRUE, but I have some reasons for
preferring to save the graph as a pdf file and use it later.

Thanks.

--Chris Ryan