Is there a "No Units" (i.e., dimensionless) unit?

Question

I would like to be able to call the Quantity function with a null unit so that it returns the original dimensionless value. For example,

Quantity[3.0,"NoUnits"]

would return 3.0. Is there a dimensionless unit?

If it isn't there, I assume you could just add a definition to Quantity. What use of that do you have in mind? — Rojo, Dec 21 '12 at 21:34
@Rojo: I run Monte Carlo simulations which output huge quantities of data with varying dimensions, so I created a data dictionary which describes each data type, including the units. When the simulation results are loaded into Mathematica, I use the data dictionary to attach units. However, some of the data types are dimensionless and rather than having a special "dimensionless" case for the code that calls Quantity, I'd rather have Quantity handle it. — Cassini, Dec 21 '12 at 21:38

score 27 · Accepted Answer · edited Sep 15 '17 at 22:28

27

I believe you can use "DimensionlessUnit" to get the desired result:

Quantity[3, "DimensionlessUnit"]

(note this is the unit produced by QuantityUnit on a dimensionless value):

QuantityUnit[3]

"DimensionlessUnit"

edited Sep 15 '17 at 22:28

answered Dec 21 '12 at 21:55

nikko

Deleting my answer, +1 – Rojo Dec 21 '12 at 21:58
Perfect! Thanks! – Cassini Dec 21 '12 at 21:58
3

@Rojo: I still found your answer helpful because it forced me to (finally) learn something about unprotecting symbols. I think you should keep your answer. – Cassini Dec 21 '12 at 22:00

1 Answers1