dsiUnits 3.0.1

This is a Python module for handling the SI units as objects in Python, parsing them from strings and converting them to Latex and Unicode, as well as performing math operations and calculating scale factors.

D-SI Parser

This library converts D-SI unit strings to Latex. And is able to perform math operations *, / and power with the D-SI units as well as checked weather teh can be converted into each other with scalar multiplication.

Javascript version

The Javascript version of this library has moved to https://gitlab1.ptb.de/digitaldynamicmeasurement/dsiunits-js/

Installation

pip install dsiUnits

Usage

The Constructor DsiUnit(str) will parse the string and create a DsiUnit object. BIMP-SI-RP strings are also supported and will be converted to D-SI units. The DsiUnit object has the following methods:

• to_latex(): returns the Latex representation of the unit.
• to_utf8(): returns the UTF8 representation of the unit.
• is_scalably_equal_to(other): checks whether the unit is equal to another unit with scalar multiplication.
• to_sirp(pid=False): returns the SIRP representation of the unit. If pid is true the PID as URL is returned.

And following magic functions:

• __mul__(other): "*" multiplies the unit with another unit or a scalar

• __truediv__(other): "/" divides the unit by another unit or a scalar

• __pow__(other): "**" raises the unit to the power of another unit or a scalar

• __eq__(other): "==" checks whether the unit is equal to another unit

• __str__: "str()" returns the string representation of the unit

• __repr__: returns the string representation of the unit

• to_base_unit_tree(): returns the base unit tree of the unit.

• reduce_fraction(): reduces the fraction of the unit by resolving all \per and combining same units by exponent addition.

• sort_tree(): sorts the base unit tree of the unit.

from dsi_unit import DsiUnit

unit = DsiUnit(r'\metre\second\tothe{-1}')
latexStr = unit.to_latex()
print(latexStr)

from dsi_unit import DsiUnit

mps = DsiUnit(r'\metre\second\tothe{-1}')
kmh = DsiUnit(r'\kilo\metre\per\hour')
scale_factor, base_unit = mps.is_scalably_equal_to(kmh)
print(
    f"The unit {mps} is equal to {kmh} with a factor of {scale_factor} and base unit {base_unit}"
)

For more usage examples see the Example Notebook, as well as the pytest file.

D-SI unit regex

This project also generates a RegEx that can be used to test whether a string conforms to the syntax of D-SI units. You can find the up-to-date text files here: https://gitlab1.ptb.de/digitaldynamicmeasurement/dsiUnits/-/jobs/artifacts/main/browse?job=generate_regex.

More details on the RegEx generator, including documentation of the different variants, can be found in the doc/ folder: English, German