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Class: Power

The Power class is a subclass of Variable designed to represent the rate at which work is done or energy is transferred. It ensures accurate calculations by storing all values internally in its base SI unit, Watts (W).

Supported Units

The following units are supported for initialization and conversion.

Unit str Conversion Factor to Watts (W)
Watts W 1
kilowatts kW 103
megawatts MW 106
mechanical horsepower hp 745.7
British Thermal Units per hour BTU/h 0.29307107

Class Reference

class Power(value, units='W')

A class for handling power measurements with automatic unit conversion.

Parameters:

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

Raises:

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

Examples: 

# Create a Power object of 1000 Watts  
>>> p1 = Power(1000)

# Create a Power object of 1 kilowatt  
>>> p2 = Power(1, "kW")

# Create a Power object of 1.34 horsepower  
>>> p4 = Power(1.34, "hp")

Properties

Property Type Description
.value float The numeric value of the power, always in Watts (W). 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 Power 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:

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

Raises:

  • ValueError : If target_unit is not a valid unit.

Examples: 

# Initialize a power of 1000 W  
>>> power_W = Power(1000)

# Convert to kilowatts  
>>> power_kW = power_W.to("kW")

>>> print(power_kW)  
1.0 kW

String Representation

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