Cheetah Rounding Values

[rich T]

Is there a way cheetah can round a value to 1 decimal point or does the rounding need to be performed in an SQL statement first?

[Andrew Milner]

See customisation guide

[Tom Keffer]

See the section Formatting options in the Customizing Guide. There are also some examples in the next section.

On Fri, Apr 24, 2020 at 9:28 PM rich T <storm...@gmail.com> wrote:

Is there a way cheetah can round a value to 1 decimal point or does the rounding need to be performed in an SQL statement first?

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[rich T]

Thanks I tried your suggestions, but still does not round to the decimal point. I did create a new tag. Do I need to create a new search list extension to allow formatting?

Thanks 

Rich

[gjr80]

Rich,

How you format data in a Cheetah generated report really depends on the source of the data. If you are using a WeeWX generated tag, eg $current.outTemp, then you have all the formatting and unit conversion options of a WeeWX tag available to you (as linked by Tom). If the data comes from some inline python in your Cheetah template then you are responsible for formatting the data, for example, if your template had the following:

#set $pie_temperature = 22/7

and you wanted to use $pie_temperature in your template then you would be responsible for formatting the output, you might do something like:

#set $pie_temperature_2d = round($pie_temperature, 2)

and then use $pie_temperature_2d to display $pie_temperature to two decimal places (or you might just have used #set $pie_temperature = round(22/7, 2) up front). Bottom line is, formatting/unit conversion etc is your problem, not WeeWX'

If your data comes from a Search List Extension (SLE) then it depends on what the SLE provides. Let's say the SLE provides a tag $pie_temp that is a temperature. If $pie_temp is just a number then just like $pie_temperature you need to format it yourself. However, is the SLE is a little more sophisticated and provides $pie_temp as a special WeeWX object known as a ValueHelper, then $pie_temp has all of the formatting and unit conversion abilities of a WeeWX tag such as $current.outTemp. Generally speaking it is quite easy to have a SLE return a ValueHelper(), whilst it does make the SLE code a little more complex it provides for a much more flexible output.

At the end of the day a SLE does not allow formatting per se, rather it is the type of output from a SLE that determines what formatting/unit conversion is available. Have a read of the section Defining new tags in the Customization Guide, it covers ValueHelpers and SLEs with examples.

Gary

[Andrew Milner]

If you are using weewx tags it would be something like

$current.outTemp.format("%.1f") for one decimal place

[rich T]

Thanks everyone who provided suggestions. Using Gary's suggestion and it finally works.

#set Daily_Max = $day.outTemp.max

#set Departure_Temp_Max = $Daily_Max.raw - $day.outTemp.historical_max_avg.raw

#set Departure_Temp_Max = round($Departure_Temp_Max, 1)