R packages are a collection of related functions, possibly with data, built to tackle a specific problem. R comes with several pre-installed packages such as base, stats, datasets etc. These packages pretty much cover all that is needed for basic data science exercises. However sometimes we need to do more. R allows installation of external R packages for use. The R community keeps building advanced methodologies in the form of R packages and they are publicly available. In the following I’ll describe how to install packages on your machine and how to use them.
The Comprehensive R Archive Network, CRAN for short, is possibly the only one you need to know for now. There are other archives, such as bioconductor (https://www.bioconductor.org/) with its own framework and installation procedure.
How to find the name your R package of interest?
There are various overview sites cataloguing packages, however the easiest way to find your R package is to google with your key words of interest. For example lets say we want to read/write SPSS file formats. Simply google ‘read write spss r package’. There will be many pages with links and descriptions on several packages which can help you on your query. I have reviewed some of the packages, one of which being the package haven, and that is the one we are going to install next.
Install packages
CRAN is the default archive accessible from R and packages can be installed either by entering the function call install.packages("your-package-name") in the console:
install.packages("haven")The same can be achieved by selecting the Packages pane and clicking install and in the pop-up dialogue enter the package name, i.e. haven
You only need to install a package once.
How to use an installed R package?
You’ve just installed an R package, to use the functions in the package you’ll need one more command:
library(haven)This call will load the package and gives you direct access to the functions inside the package. If you close the R session, then the next time you start R, you’ll need to load the package again.
A package is installed once, but it must be loaded with each new R session to be able to use it.
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