The function GetSystem(system) returns all units in a system of units.

For an existing system system, the call AddSystem(system, GetSystem(system)) recreates an equivalent system. The calling sequence AddSystem(system, check, GetSystem(system), new_unit) redefines the system by including new_unit and ensuring that new_unit does not have the same dimension as any of the existing units in system.

$\mathrm{with}\left(\mathrm{Units}\right)\:$

Automatically loading the Units[Simple] subpackage

$\mathrm{GetSystem}\left(\'\mathrm{CGS}\'\right)$

$\frac{{\mathrm{erg}}_{\mathrm{standard}}}{{\mathrm{second}}_{\mathrm{SI}}},{\mathrm{radian}}_{\mathrm{SI}},{\mathrm{centimeter}}_{\mathrm{SI}}^3,{\mathrm{centimeter}}_{\mathrm{SI}},{\mathrm{steradian}}_{\mathrm{SI}},{\mathrm{dyne}}_{\mathrm{standard}},{\mathrm{erg}}_{\mathrm{standard}},{\mathrm{gal}}_{\mathrm{standard}},{\mathrm{gram}}_{\mathrm{SI}},{\mathrm{dollar}}_{\mathrm{US}},{\mathrm{second}}_{\mathrm{SI}},{\mathrm{barye}}_{\mathrm{standard}},{\mathrm{kelvin}}_{\mathrm{SI}},{\mathrm{centimeter}}_{\mathrm{SI}}^2,{\mathrm{kyne}}_{\mathrm{standard}},{\mathrm{dyne}}_{\mathrm{standard}}{\mathrm{centimeter}}_{\mathrm{SI}}\left(\mathrm{radius}\right)$

$\mathrm{AddSystem}\left(\'\mathrm{FHF}\'\,\'\mathrm{check}\'\,\'\mathrm{furlong}\'\,\'{\mathrm{hundredweight}}_{\mathrm{long}}\'\,\'\mathrm{fortnight}\'\right)$

$\mathrm{GetSystem}\left(\'\mathrm{FHF}\'\right)$

${\mathrm{furlong}}_{\mathrm{standard}},{\mathrm{hundredweight}}_{\mathrm{long}},{\mathrm{fortnight}}_{\mathrm{standard}}$

$\mathrm{AddSystem}\left(\'\mathrm{MKSA}\'\,\mathrm{GetSystem}\left(\'\mathrm{MKS}\'\right)\,\'\mathrm{ampere}\'\right)$

${\mathrm{infolevel}}_{\mathrm{Units}}≔1\:$

$\mathrm{convert}\left(96485.309\,\'\mathrm{system}\'\,\'\mathrm{electron}\'\,\'\mathrm{MKS}\'\right)$

Error, (in convert/system) cannot represent the given unit in the system `MKS`

$\mathrm{convert}\left(96485.309\,\'\mathrm{system}\'\,\'\mathrm{electron}\'\,\'\mathrm{MKSA}\'\right)$

convert/system: converting to the units A*s

$1.545865063\times {10}^{\mathrm{-14}}$