pythondecimalpint

Python - pint - Can I set default type to Decimal?

Im using pint module in a project. Objects in my project handle numerical data as Decimals. When I set simple pint units to a Decimal, it works:

>>> import pint
>>> from decimal import Decimal as D
>>> ureg = pint.UnitRegistry()
>>> D(10) * ureg.kN
<Quantity(10, 'kilonewton')>

But, if I try to add a second unit, it breaks. Building kiloNewton*meters in this example:

>>> D(10) * ureg.kN * ureg.m
TypeError: unsupported operand type(s) for *: 'decimal.Decimal' and 'float'

I'm using this hack:

>>> a = D(1) * ureg.kN
>>> b = D(1) * ureg.m
>>> unit_kNm = a * b
>>> D(10) * unit_kNm
<Quantity(10, 'kilonewton * meter')>

I understand why it happens. I'm looking for a solution to set up pint as I want.

Solution

  • This works:

    >>> D(10) * (ureg.kN * ureg.m)
<Quantity(10, 'kilonewton * meter')>

    And this too:

    >>> Q = ureg.Quantity
>>> Q(D(10), "kN*m")
<Quantity(10, 'kilonewton * meter')>