Uniter

Is python package, that can handle unit conversion with easy syntax. Comes with ability to perform mathematical operations, and parsing from human-readable string.

Features

• Unit conversion between metric and imperial units
• Mathematical operations between units:
  • Addition / Subtraction
  • Multiplication / Division / Floor division
  • Power
• Logical (comparison) operations between units
• Parsing from humar-readable string
• Ability to add custom units
• Adding formulas to create relation between units of different physics quantity (e.g. ohm's law)

Syntax

Here are some examples of features, including bad one to show you what you should not do while using all of these aspects.

Conversion

from uniter.units import *

print(DM(80).convert_to(M))  # prints out 8m in Unit object
print(DM(80)[M])  # same thing but shorter syntax
print(DM(80)[KG])  # raises TypeError: Illegal conversion from Length to object 

Addition / Subtraction

• Converts to last used unit in calculation

from uniter.units import *

print(KM(50) + M(30))  # prints out 5030m in Unit object
print(KM(50) - M(30))  # prints out 4070m in Unit object
print(KM(50) - KG(30))  # raise TypeError: Subtraction of non-equal units (Length - Mass)

Multiplication / Division / Floor division

• One of mul/div values needs to be int/float, not Unit type

from uniter.units import *

print(KM(30) * 2)  # prints out 900km in Unit object
print(KM(30) * 80)  # prints out 2400km in Unit object
print(KM(30) / 6)  # prints out 5km in Unit object
print(KM(8) // 6)  # prints out 1km in Unit object
print(KM(8) * KG(6))  # TypeError: Multiplication of Unit with KG, use int/float instead!

Power

from uniter.units import *

print(KM(2) ** 16)  # prints out 65536km in Unit object
print(KM(2) ** KM(3))  # Power of Unit with KM, use int/float instead!

Parsing string to Uniter units

import uniter

print(uniter.parse("2m + 5km"))  # returns 5.002km in Unit object

Custom quantity/units

Before creation of your custom units, you need to know that units are structurized as inheritance of Unit (Base Class) -> {Your name of unit here} -> {Name of unit}. This structure can basically handle that you cannot convert your unit to another incompatible units.

Example of structuring Length and Mass quatities

Unit
├─── Length
│    ├─── KM
│    ├─── M
│    ├─── DM
│    ├─── CM
│    └─── ...
└─── Mass
     ├─── KG
     ├─── G
     ├─── MG
     └─── ...

Now for creation, for making basic units using prefixes like k (kilo), m (mili), M (mega) etc. you can just use defined decorators in Uniter.py file like that:

from uniter.Uniter import Unit, Unitor, Quantitor, UnitType


# In this example I am using keywords arguments to make it clearer for you

# Creates physics quantity of your name and sign
@Quantitor(sign="EQ")
class ExampleQuantity(Unit): pass


# Creating unit of out ExampleQuantity quantity:
#
# - Multiplier is difference between this unit and default one
#
# - IF MULTUPLIER IS 1 THEN THIS UNIT IS CONSIDERED AS DEFAULT
#
# - I've also defined unit type, this is not required, 
#   it is used to filter out specific type of units
@Unitor(symbol="fU", mp=1, unit_type=UnitType.METRIC)
class FirstU(ExampleQuantity): pass

Add custom calculation method

If you are trying to make quantity with different type of calculation, than a regular units multiplication or division, you can define it via __conv__(self, unit) method which returns float.

Here i will show you piece of my code from Angle.py:

from uniter.Uniter import Unit, Quantitor


@Quantitor("°")
class Angle(Unit):
  def __conv__(self, unit):
    from math import pi, degrees, radians
    DEGS = [DEG, MOA, SOA]
    if self.__class__ in DEGS and unit in DEGS:
      return super().__conv__(unit)  # type: ignore
    elif self.__class__ in DEGS and unit is RAD:
      return radians(float(self[DEG]))
    elif self.__class__ is RAD and unit in DEGS:
      return float(DEG(degrees(float(self)))[unit])


...  # other units