I\'m having problem installing any package, also from package archive. In this case showing error trying to install ggplot2:
* installing *source* package ‘g
Your upgrade to Ubuntu 15.10 meant that the ICU library went from version 52 to a newer version (55, if I recall). But the stringi package was built against 52, and is now broken. That can happen to your R packages when they are outside of the Ubuntu package management system.
So you need to re-install stringi, which is required by ggplot2, and then ggplot2 will install and also load, avoiding the erorr you.
You could avoid these upgrade problems by using the pre-built versions of ggplot2 and its dependencies: do sudo apt-get install r-cran-ggplot2.