Question: I am trying to install **"rpart"** package in R. But I am getting the following error.

```
> install.packages('rpart')
Warning in install.packages("rpart") :
  argument 'lib' is missing: using '/home/sandeep/R/i686-pc-linux-gnu-library/2.11'
Warning message:
In getDependencies(pkgs, dependencies, available, lib) :
  package ‘rpart’ is not available

```

Can anyone please tell whats the error about? How to solve?

Answer: 
A tip to start: If you're not sure whether you have a package already, you can use eg the function `find.package()` to check:

```
> find.package('rpart')
[1] "D:/R/library/rpart"
> find.package('lololool')
Error in find.package("lololool") : there is no package called 'lololool'

```

The problem is not so much that it is installed by default. It can be downloaded and installed from CRAN without problem using `install.packages('rpart')`, but if you check at the [package page on CRAN](http://cran.r-project.org/web/packages/rpart/index.html), you see a very important line:

```
Depends:    R (≥ 2.13.0), graphics, stats, grDevices

```

which tells you that it is only available for R 2.13 and following versions. From your error, I deduce you still run 2.11. Quite some packages are not available for that old R version from CRAN any more, so you better update your R. Otherwise you'll run into this problem more often. 

Be aware that if you run Debian, you'll have to do a bit more effort, as the default R in debian is always outdated. Just in case, you find the directions to do that [here](http://cran.r-project.org/bin/linux/debian/).
I found that once I restarted RStudio that I was able to install the package and find.package() showed I did, now, have the packages.