R packages - r - learn r - r programming
- R packages are a collection of R functions, complied code and sample data.
- They are stored under a directory called "library" in the R environment.
- By default, R installs a set of packages during installation. More packages are added later, when they are needed for some specific purpose.
- When we start the R console, only the default packages are available by default.
- Other packages which are already installed have to be loaded explicitly to be used by the R program that is going to use them.
- All the packages available in R language are listed at R Packages.
- Below is a list of commands to be used to check, verify and use the R packages.
Check Available R Packages
- Get library locations containing R packages,
.libPaths()
- When we execute the above code, it produces the following result.
- It may vary depending on the local settings of your pc.
"C:/Program Files/R/R-3.2.2/library"
- Get the list of all the packages installed
library()
- When we execute the above code, it produces the following result.
- It may vary depending on the local settings of your pc.
Packages in library ‘C:/Program Files/R/R-3.2.2/library’:
base The R Base Package
boot Bootstrap Functions (Originally by Angelo Canty
for S)
class Functions for Classification
cluster "Finding Groups in Data": Cluster Analysis
Extended Rousseeuw et al.
codetools Code Analysis Tools for R
compiler The R Compiler Package
- Get all packages currently loaded in the R environment
search()
- When we execute the above code, it produces the following result.
- It may vary depending on the local settings of your pc.
".GlobalEnv" "package:stats" "package:graphics"
"package:grDevices" "package:utils" "package:datasets"
"package:methods" "Autoloads" "package:base"
Install a New Package
- There are two ways to add new R packages.
- One is installing directly from the CRAN directory and another is downloading the package to your local system and installing it manually.
Install directly from CRAN
- The following command gets the packages directly from CRAN webpage and installs the package in the R environment.
- You may be prompted to choose a nearest mirror.
- Choose the one appropriate to your location.
install.packages("Package Name")
# Install the package named "XML".
install.packages("XML")
- Install package manually
- Go to the link R Packages
- Save the package as a .zip file in a suitable location in the local system.
- Now you can run the following command to install this package in the R environment.
install.packages(file_name_with_path, repos = NULL, type ="source")
# Install the package named "XML"
install.packages("E:/XML_3.98-1.3.zip", repos = NULL, type ="source")
Load Package to Library
- Before a package can be used in the code, it must be loaded to the current R environment.
- You also need to load a package that is already installed previously but not available in the current environment.
- A package is loaded using the following command −
library("package Name", lib.loc = "path to library")
# Load the package named "XML"
install.packages("E:/XML_3.98-1.3.zip", repos = NULL, type = "source")