Frequenz Quantities Library

Introduction

This library provide types for holding quantities with units. The main goal is to avoid mistakes while working with different types of quantities, for example avoiding adding a length to a time.

It also prevents mistakes when operating between the same quantity but in different units, like adding a power in Joules to a power in Watts without converting one of them.

Quantities store the value in a base unit, and then provide methods to get that quantity as a particular unit.

Installation

Using pip

python3 -m pip install frequenz-quantities

Using pyproject.toml

Add this to your pyproject.toml file:

[project]
dependencies = [
    "frequenz-quantities >= 1.0.0, < 2"
]

[!NOTE] We recommend pinning the dependency to the latest version for programs, like "frequenz-quantities == 1.0.0", and specifying a version range spanning one major version for libraries, like "frequenz-quantities >= 1.0.0, < 2". We follow semver.

Quick Start

from frequenz.quantities import Power, Current, Voltage

# Create quantities using unit-specific constructors
power = Power.from_watts(1500.0)
current = Current.from_amperes(10.0)
voltage = Voltage.from_volts(230.0)

# Perform operations between quantities
total_power = power + Power.from_kilowatts(2.0)
print(f"Total power: {total_power}")  # Total power: 3500 W

# Convert to different units
print(f"Power in kW: {total_power.as_kilowatts()}")  # Power in kW: 3.5

# Type safety prevents invalid operations
# This would raise a TypeError:
# invalid = power + current  # Can't add power and current!

Documentation

For more information on how to use this library and examples, please check the Documentation website.

Supported Platforms

The following platforms are officially supported (tested):

• Python: 3.11
• Operating System: Ubuntu Linux 20.04
• Architectures: amd64, arm64

Contributing

If you want to know how to build this project and contribute to it, please check out the Contributing Guide.