Running examples in 'constants-Ex.R' failed
The error most likely occurred in:

> ### Name: syms
> ### Title: Lists of Constants
> ### Aliases: syms syms_with_errors syms_with_units syms_with_quantities
> ### Keywords: datasets
> 
> ### ** Examples
> 
> # the speed of light
> syms$c0
[1] 299792458
> # use the constants in a local environment
> with(syms, c0)
[1] 299792458
> 
> # attach only Planck-related constants
> (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(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
Error: object 'h' not found
Execution halted