Units

Module containing global unit registry.

The Pint package supports arithmetic of physical quantities, which are combinations of numerical values and units of measurement. The units of a quantity come from Pint’s unit registry. This module contains a unit registry, named u, based on Pint’s unit registry. It also defines a few additional units.

Frequently Used Units and Constants in `u`

Prefixes for Metric Units

pico- = 1e-12 = p-
nano- = 1e-9 = n-
micro- = 1e-6 = u- = µ-
milli- = 1e-3 = m-
centi- = 1e-2 = c-
deci- = 1e-1 = d-
deca- = 1e+1 = da-
hecto- = 1e2 = h-
kilo- = 1e3 = k-
mega- = 1e6 = M-
giga- = 1e9 = G-
tera- = 1e12 = T-

Units of Length

u.meter = u.metre = u.m
u.inch
u.foot = u.ft
u.yard = u.yd
u.mile = u.mi

Units of Mass

u.gram = u.g
u.metric_ton = u.tonne = u.t
u.ounce = u.oz
u.pound = u.lb
u.ton
u.atomic_mass_unit = u.amu

Units of Time

u.second = u.sec = u.s
u.minute = u.min
u.hour = u.hr
u.day
u.week
u.year

Units of Temperature

u.kelvin = u.degK
u.celsius = u.degC
u.fahrenheit = u.degF

Units of Angle

u.revolution = u.rev
u.radian = u.rad
u.degree = u.deg

Units of Force

u.newton = u.N
u.gram_force = u.gf
u.kilogram_force = u.kgf
u.pound_force = u.lbf
u.ton_force
u.kip

Units of Frequency

u.hertz = u.Hz
u.revolutions_per_minute = u.rpm

Units of Money

u.dollar = u.USD
u.lempira = u.HNL

Units of Power

u.watt = u.W
u.horsepower = u.hp

Units of Pressure

u.pascal = u.Pa
u.bar
u.atmosphere = u.atm
u.torr
u.millimeter_Hg = u.mmHg

Units of Volume

u.liter = u.litre = u.L
u.cubic_centimeter = u.cc
u.gallon = u.gal
u.quart = u.qt
u.pint = u.pt
u.cup
u.fluid_ounce = u.floz
u.tablespoon = u.tbsp
u.teaspoon = tsp

Other Units

u.joule = u.J
u.mole = u.mol = u.equivalent = u.eq
u.NTU = 1.47 * (u.mg / u.L)
- This turbidity-concentration relation applies to kaolinite clay and is obtained from Coagulation behavior of polyaluminum chloride (Wei et al., 2015).

Constants

u.gravity
u.molar_gas_constant = u.R
u.avogadro_number
u.boltzmann_constant

Examples

>>> from aguaclara.core.units import u
>>> mass = 3 * u.kg
>>> height = 4 * u.m
>>> potential_energy = mass * height * u.gravity

>>> potential_energy
<Quantity(12.0, 'kilogram * meter * standard_gravity')>
>>> potential_energy.magnitude
12.0
>>> potential_energy.units
<Unit('kilogram * meter * standard_gravity')>

>>> potential_energy.to(u.joule)
<Quantity(117.6798, 'joule')>
>>> potential_energy.to_base_units()
<Quantity(117.6798, 'kilogram * meter ** 2 / second ** 2')>

aguaclara.core.units.set_sig_figs(n=4)[source]

Set the default number of significant figures used to print Pint, Pandas and NumPy value quantities.

Parameters:: n (int) – number of significant figures to display. Defaults to 4.
Examples:

>>> from aguaclara.core.units import set_sig_figs, u
>>> h = 2.5532532522352543*u.m
>>> e = 25532532522352543*u.m
>>> print('h before sigfig adjustment:',h)
h before sigfig adjustment: 2.553 meter
>>> print('e before sigfig adjustment:',e)
e before sigfig adjustment: 2.553e+16 meter
>>> set_sig_figs(10)
>>> print('h after sigfig adjustment:',h)
h after sigfig adjustment: 2.553253252 meter
>>> print('e after sigfig adjustment:',e)
e after sigfig adjustment: 2.553253252e+16 meter