title: Where are the installed R packages?
body: <p>Where are the installed R packages?</p>
  
  <p>For example, after installing packages with 'install.packages("mlbench")' and so on, only "The downloaded binary packages are in C:\Users\ABC\AppData\Local\Temp\Rtmp2XB0sh\downloaded_packages" is a piece of related info from the console messages. </p>
  
  <p>However, I fail to find them at all after scouring my computer according to package names (not just listing them with 'installed.packages()'). This question seems very difficult for me, but strangely I found almost no answer online. Where are the installed packages on the local computer?</p>