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Class: Mass

The Mass class is a subclass of Variable designed to represent a quantity of mass. It ensures accurate calculations by storing all values internally in its base SI unit, kilograms (kg).

Supported Units

The following units are supported for initialization and conversion.

Unit str Conversion Factor to Kilograms (kg)
kilograms kg 1
grams g 0.001
milligrams mg 0.000001
ton ton 1000
pounds lb 0.453592
ounces oz 0.0283495
metric tons mt 1000
micrograms ug 10−9

Class Reference

class Mass(value, units='kg')

A class for handling mass measurements with automatic unit conversion.

Parameters:

  • value : float or int
    The numeric value of the mass. Must be a non-negative number.
  • units : str, default='kg'
    The unit of the provided value. Must be one of the supported units.

Raises:

  • ValueError : If value is negative.
  • TypeError : If units is not a valid unit.

Examples: 

# Create a Mass object of 500 grams  
>>> m1 = Mass(500, "g")

# Create a Mass object of 2 kilograms  
>>> m2 = Mass(2, "kg")

Properties

Property Type Description
.value float The numeric value of the mass, always in kilograms (kg). This is the internal representation used for all calculations.
.original_value float The numeric value as provided during initialization.
.original_unit str The unit as provided during initialization.

Methods

to(target\_unit)

Returns a new Mass object converted to the target_unit. The original object remains unchanged.

Parameters:

  • target_unit : str
    The unit to convert to. Must be one of the supported units.

Returns:

  • Mass
    A new Mass object with the same value, represented in the target unit.

Raises:

  • TypeError : If target_unit is not a valid unit.

Examples: 

# Initialize a mass of 500 grams  
>>> mass_g = Mass(500, "g")

# Convert to pounds  
>>> mass_lb = mass_g.to("lb")

>>> print(mass_lb)  
1.102312 lb

String Representation

  • __str__(self) Returns a human-readable string representation of the mass, rounded to six decimal places, using its original value and unit.
  • __repr__(self)
    Returns an unambiguous string representation of the object.