Overview

The Quantity class is the primary object for performing calculations in Quantium. It binds a numerical value to a specific Unit, allowing for dimensionally-aware arithmetic, comparisons, and unit conversions.

Instantiation and Access

A Quantity object holds your value and its unit. Multiplying a number by a unit (e.g., 100 * u.m) is the standard, convenient way to create one. This operation calls the Quantity constructor and returns the resulting object.

from quantium.core.quantity import Quantity
from quantium import u

# Preferred shorthand (returns a Quantity)
dist_short = 100 * u.m

# Direct constructor (equivalent)
dist_long = Quantity(100, u.m)

assert dist_short == dist_long

Accessing values

Once you have a Quantity object, you can access its numeric value in the current unit via the .value property, or get an SI-expressed Quantity using the .si property.

time = Quantity(10, u.s)
print(time.value)       # 10.0

dist_km = Quantity(5, u.km)
print(dist_km)          # 5 km
print(dist_km.value)    # 5.0
print(dist_km.si)       # 5000 m
print(dist_km.si.value) # 5000.0