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Support for measurement units in R vectors, matricesand arrays: automatic propagation, conversion, derivationand simplification of units; raising errors in case of unitincompatibility. Compatible with the POSIXct, Date and difftimeclasses. Uses the UNIDATA udunits library and unit database forunit compatibility checking and conversion.

Documentation is provided in an R Journal publication. Cite this package as:

• Edzer Pebesma, Thomas Mailund and James Hiebert (2016). "Measurement Units in R."The R Journal, 8 (2), 486--494.DOI:10.32614/RJ-2016-061

The main unitsvignettederives from this manuscript and is kept up to date with the package development.

• Blog posts:first,second,third.
• The UNIDATAudunits2 library at GitHub.

Packageunits providesmeasurement units for R vectors: conversion, derivation, simplification and error checking:

library(units)(spd1= set_units(1:5,m/s))# Units: m/s# [1] 1 2 3 4 5(spd2= set_units(1:5,km/h))# Units: km/h# [1] 1 2 3 4 5spd1+spd2# automatic conversion# Units: m/s# [1] 1.277778 2.555556 3.833333 5.111111 6.388889spd1*spd2# unit derivation# Units: km*m/h/s# [1]  1  4  9 16 25spd1* set_units(10,s)# unit simplification# Units: m# [1] 10 20 30 40 50spd1+ set_units(10,s)# error checking#   cannot convert s into m/s

Install the release version from CRAN:

install.packages("units")

The installation of the development version from GitHub requires, e.g., theremotes package:

remotes::install_github("r-quantities/units")

If the installation fails due to a missing udunits2 system library, either install it e.g. on Ubuntu or Debian by

sudo apt-get install libudunits2-dev

on Fedora or RHEL/CentOS with

sudo dnf install udunits2-devel

or on MacOS with

brew install udunits

or equivalent in your distribution. Alternatively, install it from the sources by downloading the latest version fromUDUNITS downloads, and executing the following commands in the download directory:

tar zxf udunits-<version>.tar.gzcd ./udunits-<version>/./configuremakesudo make installsudo ldconfig

Then, retry the installation ofunits.