Rounding QuantityType<Temperature> values to 0.5 °C

[rossko57]

@AndrewFG

Which makes them i) hard to compare

I don’t see why?

@AndrewFG

messy to log

I want “21.3°C” in my message string, not “21.28478 °C”

var message = "Temperature is " + (tempItemC.state as QuantityType<Temperature>).format("%.1f%unit%")
// returns "Temperature is 10.0°C"

from

Working with Number:Temperature Items in rules

openHAB provides Quantity Type features, which can seem baffling. On top of that, Temperature type Quantities have a few quirks all of their own. These notes intend to guide the rules author. I’ve shown work examples in DSL rules language, see below for other scripts examples. All have similar features, if different syntax. Knowing what can be done is half the battle. What is a Quantity Type? Simply, Item states and rule variables may contain Quantities - that just means a number AND a unit …

Long story short - there is no easy way to round a Quantity, because the granularity, the “detents” that you are trying to round to all depends on the units you are expressing the quantity in at the time. Rounding identical quantities 1200.1m and 1.2001km to “integer” does not give the same result.