Issue converting to %

[lafrech]

I'm trying to use the new % unit introduced in #1661.

While it works to define a quantity, that can then be converted to another dimensionless unit:

>>> ureg.Quantity(1, "%")
<Quantity(1, 'percent')>
>>> ureg.Quantity(1, "%").m_as("")
0.01

it doesn't seem to work the other way around.

>>> ureg.Quantity(1, "")
<Quantity(1, 'dimensionless')>
>>> ureg.Quantity(1, "").m_as("%")
pint.errors.DefinitionSyntaxError: missing unary operator "%"

Is this a known limitation? It doesn't seem consistent.

Looks like preprocessors apply to quantity definitions but not unit expressions in Quantity.to.

I think I have a workaround that at least solves my use case:

>>> ureg.Quantity(1, "").m_as(ureg.Unit("%"))
100.0

Perhaps this cast could be done somewhere in m_as, to or further down the way.

[hgrecco]

confirmed

[mmarras]

confirmed

I think this can be closed with 0.23, no? I tried ureg.Quantity(1,'').to('%') and it works now.

[lafrech]

Indeed, this seems to be fixed in 0.23.0.

Thanks.