converting between units and equality

[yqiang]

pint 0.24.3

I would expect that when converting from say 1 lb to 16 oz and then back to lb would be equivalent, but it doesn't seem to be the case:

In [21]: from pint import UnitRegistry

In [22]: ureg = UnitRegistry()

In [23]: (1 * ureg.lb).to(ureg.oz)
Out[23]: <Quantity(16.0, 'ounce')>

In [24]: (1 * ureg.lb).to(ureg.oz) == 16 * ureg.oz
Out[24]: False

In [25]: (1 * ureg.lb).to(ureg.oz) == 16.0 * ureg.oz
Out[25]: False

It appears that it might have to do with floating point precision:

In [28]: (1 * ureg.lb).to(ureg.oz).magnitude
Out[28]: 16.000000000000004

Is this the expected behavior?

[andrewgsavage]

It appears that it might have to do with floating point precision:

correct

Is this the expected behavior?

yes, you must be careful when doing comparisons and equality checks for floats
the other option is to use decimals