constants: Reference on Constants, Units and Uncertainty
The constants package provides the CODATA internationally recommended values of the fundamental physical constants, provided as symbols for direct use within the R language. Optionally, the values with uncertainties and/or units are also provided if the ‘errors’, ‘units’ and/or ‘quantities’ packages are installed. The Committee on Data for Science and Technology (CODATA) is an interdisciplinary committee of the International Council for Science which periodically provides the internationally accepted set of values of the fundamental physical constants. This package contains the “2018 CODATA” version, published on May 2019.
Eite Tiesinga, Peter J. Mohr, David B. Newell, and Barry N. Taylor (2020). The 2018 CODATA Recommended Values of the Fundamental Physical Constants (Web Version 8.1). Database developed by J. Baker, M. Douma, and S. Kotochigova. Available at https://physics.nist.gov/cuu/Constants/, National Institute of Standards and Technology, Gaithersburg, MD 20899.
Installation
Install the release version from CRAN:
install.packages("constants")The installation from GitHub requires the remotes package.
# install.packages("remotes")
remotes::install_github("r-quantities/constants")Example
library(constants)
# the speed of light
syms$c0
#> [1] 299792458
# use the constants in a local environment
with(syms, c0)
#> [1] 299792458
# explore which constants are available
(lkp <- lookup("planck", ignore.case=TRUE))
#> symbol quantity
#> 137 nah molar Planck constant
#> 198 h Planck constant
#> 199 hev Planck constant in eV/Hz
#> 200 plkl Planck length
#> 201 plkm Planck mass
#> 202 plkmc2gev Planck mass energy equivalent in GeV
#> 203 plktmp Planck temperature
#> 204 plkt Planck time
#> 230 hbar reduced Planck constant
#> 231 hbarev reduced Planck constant in eV s
#> 232 hbcmevf reduced Planck constant times c in MeV fm
#> type value uncertainty unit
#> 137 Physico-chemical 3.990313e-10 0.0e+00 J/Hz/mol
#> 198 Universal, Adopted values 6.626070e-34 0.0e+00 J/Hz
#> 199 Universal 4.135668e-15 0.0e+00 eV/Hz
#> 200 Universal 1.616255e-35 1.8e-40 m
#> 201 Universal 2.176434e-08 2.4e-13 kg
#> 202 Universal 1.220890e+19 1.4e+14 GeV
#> 203 Universal 1.416784e+32 1.6e+27 K
#> 204 Universal 5.391247e-44 6.0e-49 s
#> 230 Universal, Adopted values 1.054572e-34 0.0e+00 J*s
#> 231 Universal 6.582120e-16 0.0e+00 eV*s
#> 232 Universal, Non-SI units 1.973270e+02 0.0e+00 fm*MeV
idx <- as.integer(rownames(lkp))
# attach the symbols to the search path and use them explicitly
attach(syms[idx])
h
#> [1] 6.62607e-34
plkl
#> [1] 1.616255e-35
# the same with uncertainty
detach(syms[idx])
attach(syms_with_errors[idx])
h
#> 6.62607(0)e-34
plkl
#> 1.61626(2)e-35
# the same with units
detach(syms_with_errors[idx])
attach(syms_with_units[idx])
h
#> 6.62607e-34 [J/Hz]
plkl
#> 1.616255e-35 [m]
# the same with everything
detach(syms_with_units[idx])
attach(syms_with_quantities[idx])
h
#> 6.62607(0)e-34 [J/Hz]
plkl
#> 1.61626(2)e-35 [m]
# the whole dataset
head(codata)
#> symbol quantity type
#> 1 mal alpha particle mass Atomic and nuclear
#> 2 malc2 alpha particle mass energy equivalent Atomic and nuclear
#> 3 malc2mev alpha particle mass energy equivalent in MeV Atomic and nuclear
#> 4 malu alpha particle mass in u Atomic and nuclear
#> 5 mmal alpha particle molar mass Atomic and nuclear
#> 6 malsme alpha particle-electron mass ratio Atomic and nuclear
#> value uncertainty unit
#> 1 6.644657e-27 2.0e-36 kg
#> 2 5.971920e-10 1.8e-19 J
#> 3 3.727379e+03 1.1e-06 MeV
#> 4 4.001506e+00 6.3e-11 u
#> 5 4.001506e-03 1.2e-12 kg/mol
#> 6 7.294300e+03 2.4e-07 1
# number of constants per type
library(magrittr)
codata %>%
tidyr::separate_rows(type, sep=", ") %>%
dplyr::count(type, sort=TRUE)
#> # A tibble: 8 x 2
#> type n
#> <chr> <int>
#> 1 Atomic and nuclear 173
#> 2 <NA> 68
#> 3 Non-SI units 36
#> 4 Electromagnetic 26
#> 5 Physico-chemical 25
#> 6 Universal 16
#> 7 Adopted values 11
#> 8 X-ray values 6