The is pint which is a Python package to define, operate and manipulate physical quantities.
- Python 2.6+, 3
- BSD licence
- Usable with numpy without patching numpy
- Handles conversions between compatible units and errors on incompatibles.
- Pure python & standalone module
```python
In [1]: import pint
In [2]: ureg = pint.UnitRegistry()
In [4]: a = 0.3 * ureg.meter
In [5]: b = 1 * ureg.inch
In [6]: a+b
Out[6]: <Quantity(0.32539999999999997, 'meter')>
In [7]: _.to(ureg.inch)
Out[7]: <Quantity(12.811023622047243, 'inch')>
In [8]: _
Out[8]: <Quantity(12.811023622047243, 'inch')>
In [9]: _ * (12 * ureg.pound_force)
Out[9]: <Quantity(153.7322834645669, 'force_pound * inch')>
In [10]: _.to(ureg.joule)
Out[10]: <Quantity(17.369415763269195, 'joule')>
In [11]: j = _
In [12]: j
Out[12]: <Quantity(17.369415763269195, 'joule')>
In [13]: j / ureg.sq_ft
Out[13]: <Quantity(17.369415763269195, 'joule / square_foot')>
In [15]: j + 2 * ureg.degC
OffsetUnitCalculusError Traceback (most recent call last)
```
Lots of units
In [20]: ', '.join(dir(ureg))
Out[20]: 'A, B, BTU, Ba, Bd, Bq, British_horsepower, Btu, C, C12_faraday,
Ci, DPI, Da, EC_therm, E_h, F, Fr, Gy, H, H2O, Hg, Hz, J, K, KPH, L,
Langley, MPH, Measurement, N, N_A, Oe, P, PPCM, PPI, PSH, Pa, P̸, Quantity,
R, Rd, S, St, Sv, T, Tbl, Tblsp, Tbsp, UK_bbl, UK_bushel, UK_cup, UK_cwt,
UK_fluid_ounce, UK_gallon, UK_gill, UK_horsepower, UK_hundredweight,
UK_pint, UK_pk, UK_quart, UK_ton, US_cwt, US_dry_barrel, US_dry_gallon,
US_dry_pint, US_dry_quart, US_fluid_dram, US_fluid_ounce, US_hundredweight,
US_liquid_cup, US_liquid_gallon, US_liquid_gill, US_liquid_ounce,
US_liquid_quart, US_pint, US_shot, US_therm, US_ton, Unit, V, VA, W, Wb, Wh,
Z_0, acre, acre_feet, acre_foot, amp, ampere, ampere_turn, amu, angstrom,
angular_degree, angular_minute, angular_second, ap_dr, ap_lb, ap_oz,
apothecary_dram, apothecary_ounce, apothecary_pound, arc_minute, arc_second,
arcdeg, arcdegree, arcmin, arcminute, arcsec, arcsecond, are,
astronomical_unit, at, atm, atmosphere, atomic_mass_unit, au, avdp_dram,
avdp_ounce, avdp_pound, avogadro_number, avoirdupois_dram,
avoirdupois_ounce, avoirdupois_pound, b, bag, bar, barad, barie, barn,
barrel, barrie, baryd, barye, baud, bbl, becquerel, beer_barrel, beer_bbl,
bit, bits_per_pixel, boiler_horsepower, boltzmann_constant, bpp, bps,
british_thermal_unit, btu, bu, bushel, byte, c, cal, calorie, candela,
candle, carat, cc, cd, celsius, centimeter, centimeter_Hg, ch_cwt, chain,
characteristic_impedance_of_vacuum, chemical_faraday, circle, circular_mils,
cmH2O, cmHg, cm_Hg, cmil, common_year, conventional_mercury,
conventional_water, convert, coulomb, count, counts_per_second, cp, cps,
cu_ft, cu_in, cu_yd, cubic_centimeter, cubic_feet, cubic_foot, cubic_inch,
cubic_yard, cup, curie, cycle, dalton, darcy, day, decitex, define, deg,
degC, degF, degK, degR, degree, delta_degC, delta_degF, denier, dgal, dot,
dots_per_inch, dpi, dqt, dr, drachm, dram, dry_barrel, dry_gallon, dry_pint,
dry_quart, dtex, dwt, dyn, dyne, e, eV, electric_constant,
electric_horsepower, electron_mass, electron_volt, elementary_charge, eon,
epsilon_0, erg, esu, esu_per_second, fahrenheit, farad, faraday, fathom, feet,
fine_structure_constant, fldr, floz, fluid_dram, fluid_ounce, fluidram, foot,
footH2O, foot_H2O, force_gram, force_kilogram, force_ounce, force_pound,
force_ton, fortnight, franklin, ft, ftH2O, furlong, g, g_0, g_n, gal, gallon,
gamma, gauss, get_base_units, get_dimensionality, get_name, get_root_units,
get_symbol, gf, gi, gilbert, gill, gr, grain, gram, gram_force, gravity, gray,
gregorian_year, h, h2o, ha, hartree, hartree_energy, hbar, hectare, henry,
hertz, hogshead, horsepower, hour, hp, hr, hydraulic_horsepower,
impedance_of_free_space, imperial_barrel, imperial_bbl, imperial_bu,
imperial_bushel, imperial_cp, imperial_cup, imperial_floz,
imperial_fluid_drachm, imperial_fluid_dram, imperial_fluid_ounce, imperial_gal,
imperial_gallon, imperial_gi, imperial_gill, imperial_peck, imperial_pint,
imperial_pk, imperial_pt, imperial_qt, imperial_quart, in, inHg, in_Hg, inch,
inch_H2O_39F, inch_H2O_60F, inch_Hg, inch_Hg_32F, inch_Hg_60F, inches,
international_feet, international_foot, international_inch,
international_inches, international_knot, international_mile,
international_steam_table_calorie, international_yard, jig, joule, julian_year,
k, kelvin, kgf, kilogram, kilogram_force, kilometer, kip, kip_per_square_inch,
knot, knot_international, kph, ksi, kt, l, langley, lb, lbf, league, leap_year,
lg_cwt, li, light_year, lightyear, link, liquid_cup, liquid_gallon,
liquid_gill, liquid_pint, liquid_quart, liter, litre, lm, load_definitions,
long_hunderweight, long_ton, lumen, lunar_month, lux, lx, ly, m, m_e, m_n, m_p,
magnetic_constant, maxwell, mercury, mercury_60F, meter, metre,
metric_horsepower, metric_ton, mho, mi, mil, mile, milenia, milenium, millenia,
millenium, milligram, milliliter, millimeter, millimeter_Hg, millimeter_Hg_0C,
min, minim, minute, mmHg, mm_Hg, mol, molar_gas_constant, mole, month, mph,
mu_0, mx, nautical_mile, nautical_miles_per_hour, neutron_mass, newton,
newtonian_constant_of_gravitation, nmi, octet, oersted, ohm, oil_barrel,
oil_bbl, ounce, ounce_force, oz, ozf, parsec, pascal, pc, pdl, peak_sun_hour, peck,
pel, pennyweight, perch, physical_faraday, pi, pica, picture_element, pint, pixel,
pixels_per_centimeter, pixels_per_inch, pk, planck_constant, point, poise, pole,
pond, pound, pound_force, pound_force_per_square_inch, poundal, pp, ppi,
printers_dpi, printers_pica, printers_point, proton_mass, psi, pt, px, qt, quad,
quadrillion_btu, quart, quarter, rad, radian, rads, rankine, rd,
refrigeration_ton, rem, revolution, revolutions_per_minute, rhe, rod, roentgen,
rpm, rps, rutherford, rydberg_constant, s, scruple, sec, second, sft, shake,
short_hunderdweight, short_ton, shot, sidereal_day, sidereal_hour,
sidereal_minute, sidereal_month, sidereal_second, sidereal_year, siemens,
sievert, slm, slpm, speed_of_light, sq_ft, sq_in, sq_mi, sq_perch, sq_pole,
sq_rod, sq_yd, square_feet, square_foot, square_inch, square_inches,
square_mile, square_rod, square_yard, sr, stF, stH, stS, stV,
standard_atmosphere, standard_gravity, standard_liter_per_minute, statC, statF,
statH, statS, statV, statampere, statcoulombs, statfarad, stathenry, statmho,
statohm, statvolt, stefan_boltzmann_constant, steradian, stere, stokes, stone,
survey_foot, survey_link, survey_mile, synodic_month, t, tTNT, tablespoon,
tblsp, tbs, tbsp, teaspoon, technical_atmosphere, tesla, tex, th, therm,
thermochemical_calorie, thm, thou, tlb, toe, ton, ton_TNT, ton_force,
ton_of_refrigeration, tonne, tonne_of_oil_equivalent, torr, toz, tropical_month,
troy_ounce, troy_pound, tsp, turn, u, unit_pole, us_statute_mile,
vacuum_permeability, vacuum_permittivity, volt, volt_ampere, water, water_39F,
water_4C, water_60F, watt, watt_hour, watthour, weber, week,
wien_frequency_displacement_law_constant, work_month, work_year, yard, yd, year,
Å, ångström, ħ, Δcelsius, Δfahrenheit, Ω, π, σ, Å'
