[question] making a unitless Quantity

[teauxfu]

how does one define or use a unitless instance of Quantity?
as distinct from a Quantity of unit 'dimensionless' which is returned when no unit is specified

assert Q_('1').units == Q_(1, None).units == ureg.dimensionless

the docs don't seem to mention their existence

I see that Quantity objects have a unitless property

pint/pint/quantity.py

Lines 461 to 464 in 9fc752c

	@property
	def unitless(self):
	""" """
	return not bool(self.to_root_units()._units)

but it seems only to be used within Quantity here in to_compact

pint/pint/quantity.py

Lines 760 to 766 in 9fc752c

	if (
	self.unitless
	or self.magnitude == 0
	or math.isnan(self.magnitude)
	or math.isinf(self.magnitude)
	):
	return self

and here

pint/pint/quantity.py

Lines 1789 to 1791 in 9fc752c

	def __ito_if_needed(self, to_units):
	if self.unitless and to_units == "radian":
	return

but after glancing about it's not apparent (to me) how one would even instantiate a unitless quantity, or otherwise what they'd be used for internally

I haven't yet fully inspected the UnitsContainer and its usage/references;
is the unitless property used when working with those?

possibly related #1277 regarding adding unitless dimensions

[keewis]

Could you explain what exactly you're seeing? ureg("1") returns a standard python int of value 1 for me, causing your assert line to fail with an AttributeError.

[teauxfu]

Could you explain what exactly you're seeing? ureg("1") returns a standard python int of value 1 for me, causing your assert line to fail with an AttributeError.

you're right! my bad -- I'm getting used to the differences between using Q_ vs ureg when making Quantitys

what I meant to comment was

assert Q_('1').units == ureg.dimensionless

to indicate how lack-of-unit is parsed as 'dimensionless' and not 'unitless'
similarly

assert Q_(1, None).units == ureg.dimensionless

[hgrecco]

I do not follow. Q_('1').units == Q_(1, None).units. If you want somehing without a units fields, then you want a numeric object not a Quantity.