A few months ago I published a post in which introduced the R software for statistical and graphical data analysis. One of the main features of R is its ability to import extensions through packages. But what is a package? An R package contains functions and/or data sets that can be loaded and unloaded at any time. This fact allows not to use more memory than necessary for each project.

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There are thousands of packages built for R, written by many different developers. Packages can be downloaded mainly from CRAN  and other repositories as Bioconductor and Omegahat. These packages have been tested and comply with all formal requirements to be considered R packages. You can find the complete list of packages available on CRAN on the following link.

If you want to install and load a package from CRAN, the process is:

1. Download the package in R:

install.packages (“package name”)

2. Load the functions and data sets of the package to the system:

library (“package name”)

From here, we can use the functions and datasets of the package. To learn more about the package we can write the following function that will show us its documentation:

help (“package name”)

Ahhh! I forgot it. We can also download packages from a web browser, and then load it into R without accessing to an official repository. In that case, we have to include the path where the downloaded package is.