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How can we list all available physical quantities in Mathematica?

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  • $\begingroup$ I believe this is a different issue, since I don't want to list the units associated with the quantities, but the names of the quantities instead. $\endgroup$ – Fred Dec 27 '16 at 3:41
  • $\begingroup$ What do you believe the difference is? The list are the names. Or have I missed something? $\endgroup$ – Edmund Dec 27 '16 at 3:45
  • $\begingroup$ The code provided on the linked question yields a list of units, not the quantities they are related to. It's different because the physical quantities names describe the nature of what's being measured in opposition to the units, which are the standards of measure. $\endgroup$ – Fred Dec 27 '16 at 3:55
  • $\begingroup$ Sounds like you are looking for UnitDimensions, correct? $\endgroup$ – Edmund Dec 27 '16 at 4:07
  • $\begingroup$ Not essentially, because those are only base dimensions. I'd like to have derived physical quantities also. $\endgroup$ – Fred Dec 27 '16 at 4:10
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Evaluate the following:

Quantity; (*only needed to establish symbol Quantity in symbol table*)
canonicalUnits = Keys @ QuantityUnits`Private`$UnitReplacementRules;

canonicalUnits is a big list. In V11.0.1

Length @ canonicalUnits

gives 4959. It contains more than just physical quantities. Here is a sample.

SeedRandom[42]; 
RandomSample[canonicalUnits, 20]

{"PlotterUnits", "AmagatDensityUnit", "Semimonthly", "Orguias", "Kiloleagues", "BrakeHorsepower", "Millioersteds", "Gigahenries", "BarrelsOfOil", "LinearInches", "RomanLibras", "LaoAtt", "Virgates", "Ris", "MegatonsOfOilEquivalentIT", "BritishMaunds", "LoschmidtConstant", "Coulombs", "Nanowatts", "Marks"}

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  • $\begingroup$ Actually, I was looking for the names of the quantities, not the units, e.g., "Time", "Lenght", etc.. $\endgroup$ – Fred Dec 27 '16 at 3:37
  • $\begingroup$ @Fred. "Time", "Length", etc. are just strings. They have no supported special meaning in Mathematica. $\endgroup$ – m_goldberg Dec 27 '16 at 4:02
  • $\begingroup$ But aren't they recongnized by QuantityVariable ? On documentation: "Supported physical quantities include both physical and chemical quantities such as "Length", "ElectricCurrent", and "ChemicalPotential", as well as mathematical and financial quantities such as "Angle" and "Money"." $\endgroup$ – Fred Dec 27 '16 at 4:04
  • $\begingroup$ When I type in free form input: magnetic flux, the output is a QuantityVariable $\endgroup$ – Fred Dec 27 '16 at 4:14

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