Units

u"[unit expression]"

Parse a string containing an expression of units and return the corresponding Quantity object with Float64 value. For example, u"km/s^2" would be parsed to Quantity(1000.0, length=1, time=-2).

Note that inside this expression, you also have access to the Constants module. So, for example, u"Constants.c^2 * Hz^2" would evaluate to the quantity corresponding to the speed of light multiplied by Hertz, squared.

uparse(s::AbstractString)

Parse a string containing an expression of units and return the corresponding Quantity object with Float64 value. For example, uparse("m/s") would be parsed to Quantity(1.0, length=1, time=-1).

Note that inside this expression, you also have access to the Constants module. So, for example, uparse("Constants.c^2 * Hz^2") would evaluate to the quantity corresponding to the speed of light multiplied by Hertz, squared.

Length in meters. Available variants: fm, pm, nm, μm (/um), cm, inch, dm, mm, ft, km, mi, Mm, Gm.

Mass in kilograms. Available variants: pg, ng, μg (/ug), mg, g.

Time in seconds. Available variants: fs, ps, ns, μs (/us), ms, min (/minute), h (/hr), day (/d), wk, yr, kyr, Myr, Gyr.

Current in Amperes. Available variants: nA, μA (/uA), mA, kA.

Temperature in Kelvin. Available variant: mK.

Luminosity in candela. Available variant: mcd.

Amount in moles. Available variant: pmol, nmol, μmol (/umol), mmol.

Charge in Coulombs.

Capacitance in Farads. Available variants: fF, pF, nF, μF (/uF), mF.

Electrical inductance in henries.

Frequency in Hertz. Available variants: nHz, μHz (/uHz), mHz, kHz, MHz, GHz.

Energy in Joules. Available variant: kJ.

Volume in liters. Available variants: μL (/uL), mL, cL, dL.

Molar concentration in molar. Available variants: pM, nM, μM (/uM), mM.

Force in Newtons. Available variants: μN (/uN), mN, kN.

Pressure in Pascals. Available variants: μPa (/uPa), mPa, kPa.

Electrical conductance, electric susceptance, and electric admittance in siemens. Available variants: nS, μS (/uS), mS, kS, MS, GS.

Magnetic flux density in Teslas. Available variants: Gauss

Pressure in Torr. Available variants: mTorr.

Voltage in Volts. Available variants: pV, nV, μV (/uV), mV, kV, MV, GV.

Power in Watts. Available variants: mW, kW, MW, GW.

Magnetic flux in webers. Available variants: nWb, μWb (/uWb), mWb.

Pressure in bars. Available variants: mbar.

Pressure in mmHg.

Angle in radians. Note that the SI definition is simply 1 rad = 1, so use symbolic units to avoid this. Available variants: nrad, μrad (/urad), mrad, deg, arcmin, arcsec, μarcsec (/uarcsec), marcsec.

Solid angle in steradians. Note that the SI definition is simply 1 sr = 1, so use symbolic units to avoid this.

Resistance in Ohms. Available variant: nΩ, μΩ (/uΩ), mΩ, kΩ, MΩ, GΩ. Also available is ASCII ohm (with variants nohm, μohm (/uohm), mohm, kohm, Mohm, Gohm).

@register_unit symbol value

Register a new unit under the given symbol to have a particular value.

Example

julia> @register_unit MyVolt 1.5u"V"

This will register a new unit MyVolt with a value of 1.5u"V". You can then use this unit in your calculations:

julia> x = 20us"MyVolt^2"
20.0 MyVolt²

julia> y = 2.5us"A"
2.5 A

julia> x * y^2 |> us"W^2"
281.25 W²

julia> x * y^2 |> us"W^2" |> sqrt |> uexpand
16.77050983124842 m² kg s⁻³

ua"unit"

Parse a string containing an affine unit expression. Currently only supports °C (or degC) and °F (or degF).

For example:

room_temp = 22ua"degC"  # The multiplication returns a Quantity

aff_uparse(s::AbstractString)

Parse a string into an affine unit (°C/degC, °F/degF). Function equivalent of ua"unit".

AffineUnit{R}

A simple struct for representing affine units like Celsius and Fahrenheit. This is not part of the AbstractDimensions hierarchy.

AffineUnit only supports scalar multiplication in the form number * unit (e.g., 22ua"degC"), which immediately converts it to a regular Quantity{Float64,Dimensions{R}}. Other operations like unit * number, division, addition, or subtraction with AffineUnit are not supported.