Hello, Michael and welcome to WeeWX. Would it work if I did something like > seven_day_stats1 = TimespanBinder .... > seven_day_stats2 = TimespanBinder .... > seven_day_stats = seven_day_stats1 - seven_day_stats2
Unfortunately, no, because there is no subtraction operator defined for type TimespanBinder. Why not just use the existing tag $trend <http://weewx.com/docs/customizing.htm#_________Tag_$trend_______>? If that's not what you had in mind, try hacking object TrendObj to get exactly what you want. -tk On Tue, Nov 28, 2017 at 5:17 PM, Michael Hornsby < [email protected]> wrote: > Hi > > I'm migrating from wview and very excited with what can be done with > weewx. At the moment I have php code and custom C code and I can see I can > create a much better package with weewx. > > I'm trying to get my head around how a can construct a search list > extension so I can find the change in a value from a week , month or year > ago > > For example in a template I have this > $week.outHumidity.avg.raw - $week($weeks_ago=1).outHumidity.avg.raw > > I want to know compared to last week / month / year whats the difference > in the average temp , total rain etc > > I'm looking at the example below and thinking ok. So I need to run the > stats for two periods and subtract them. > > > week_dt = datetime.date.fromtimestamp(timespan.stop) - \ > > datetime.timedelta(weeks=1) > # 5 > # Convert it to unix epoch time: > week_ts = time.mktime(week_dt.timetuple()) > # 6 > # Form a TimespanBinder object, using the time span we just > # calculated: > seven_day_stats = TimespanBinder(TimeSpan(week_ts, timespan.stop), > db_lookup, > formatter=self.generator.formatter, > converter=self.generator.converter, > skin_dict=self.generator.skin_dict) > > > > Would it work if I did something like > > seven_day_stats1 = TimespanBinder .... > seven_day_stats2 = TimespanBinder .... > > seven_day_stats = seven_day_stats1 - seven_day_stats2 > > > Thanks - I contributed a few features to wview. Hopefully I can do the > same with weewx. > > Cheers > Michael > > -- > You received this message because you are subscribed to the Google Groups > "weewx-user" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
