Peter Otten <__pete...@web.de> wrote:
> c...@isbd.net wrote:
>
> > I have a dictionary as follows:-
> >
> > {
> > u'StarterAmps1': Row(id=4, ain=u'AIN3', name=u'StarterAmps1',
> > conv=6834.374834509803, Description=u'Starter Amps'), u'LeisureVolts':
> > Row(id=1, ain=u'AIN0', name=u'LeisureVolts', conv=29.01374215995874,
> > Description=u'Leisure Volts'), u'RudderPos': Row(id=6, ain=u'AIN5',
> > name=u'RudderPos', conv=0.028125, Description=u'Rudder Position'), u'xx':
> > Row(id=7, ain=u'AIN6', name=u'xx', conv=0.028125, Description=u''),
> > u'LeisureAmps1': Row(id=3, ain=u'AIN2', name=u'LeisureAmps1',
> > conv=32.727273081945, Description=u'Leisure Amps'), u'StarterVolts':
> > Row(id=2, ain=u'AIN1', name=u'StarterVolts', conv=28.94469628911757,
> > Description=u'Starter Volts') }
> >
> > I want to output a menu to a user comprising some parts of the
> > dictionary (ain and Description) sorted by ain.
> >
> > Is there some incantation of sorted() that will do what I want? I
> > can't quite fathom out the 'key=' parameter needed to sort it by the
> > tuple item. Maybe I need a cmp= ?
> >
> > E.g. I want to do something like:-
> >
> > for meas in sorted(adc.cfg, key=???):
> > print(adc.cfg[meas].ain, adc.cfg[meas].Description)
> >
> > What's needed in the ???
>
> for meas in sorted(adc.cfg, key=lambda key: adc.cfg[key].ain):
> print(adc.cfg[meas].ain, adc.cfg[meas].Description)
>
Brilliant, worked perfectly, thank you. The bit I didn't understamd was
that 'lambda' bit, but I just looked it up and I'm a bit clearer now.
> or simpler
>
> for row in sorted(adc.cfg.values(), key=operator.attrgetter("ain"))
> print(row.ain, row.Description)
>
I tried this, I got:-
Traceback (most recent call last):
File "/home/chris/bin/calibrate.py", line 24, in <module>
for meas in sorted(adc.cfg.values,
key=operator.attrgetter("ain")):
NameError: name 'operator' is not defined
I must admit that it's the bits like 'operator' in the parameters that
I can't really understand where they come from.
> or even
>
> for row in sorted(
> map(operator.attrgetter("ain", "Description"), adc.cfg.values())):
> print(*row)
>
--
Chris Green
ยท
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