In edwardpmorris/unitlabels: Format parameter and unit labels for insertion in R, Rmarkdown and LaTeX

Scientific documents often require the use of relatively complicated terms for quantities and their units. Typing these out as 'R expressions', 'Markdown' or $\LaTeX$ can be tedious. So far, markdown does not contain a convenient mechanism for including 'short-hand' version of a quanity or unit labels.

unitlabels is a simple package that allows users to specify 'short-hand' codes for quanity or unit labels and translations into different markup. So far only 'R expressions' and 'Rmarkdown' are supported.

Using unitlabels

Three functions are available ul, uls and ulu, which return combined 'quantity-units symbol', 'quantity symbol' and 'units symbol', respectively.

Lets get started by loading the package:

# load the package
library(unitlabels)

Within an Rmarkdown document('.Rmd') we can now insert formatted text by calling the appropriate R function 'in-line'. Note for combinations of quantities and units, the 2 short-hand codes should be combined and delimited by a full stop, for example Temperature in degrees Celcius is:

# return Rmarkdown label for temperature in degrees Celcius
ul("T.degC", "md")

• "T.degC" is our user defined shortand for r ul("T.degC", "md").
• r uls("T", "md") was 25 r ulu("degC","md").

Setting the output= option to R returns labels as 'R expressions' ready to be used in plots, for example:

plot(1:10,1:10, ylab = ul("T.degC", "R"), xlab = ul("Tsw.degC", "R"))

Defining short-hand quantity units labels

So far the short-hand quantity units labels are stored in a definitions.csv file within the package directory extdata. To find the file path on your system use:

system.file("extdata", package = "unitlabels")

This file can be edited and saved by the user, furthermore facilities to define the path to a specific definitions file are provided. NOTE: test if this works!

To see which short-hand quantities and unit labels are available we can directly access this file and produce a table:

require(unitlabels)
def <- system.file("extdata", package = "unitlabels")
def <- paste0(def,"/definitions.csv")
def <- read.csv2(def, as.is = T)
knitr::kable(def[,c("standard.name", "sh.symbol", "symbol.md")])
knitr::kable(def[,c("standard.name", "sh.units", "units.md")])

edwardpmorris/unitlabels documentation built on May 15, 2019, 11:03 p.m.