Coordinate description can't be extracted as formatted date-time

[alastair-gemmell]

Submitted on behalf of an Iris user who isn't on GitHub:​

The code for generating this this string:

DimCoord([2020-08-13 00:00:00], standard_name='time', calendar='gregorian', long_name='time', var_name='time')

... is a complex combination of cf_units and numpy, and there is no public API for just getting 2020-08-13 00:00:00 alone.

It is possible to generate the string using your own code:

coord = cube.coord('time')
dt = coord.units.num2date(coord.points[i])
desired_string = str(dt)

...but it would be more useful if there was a public API for doing it.

[rcomer]

I just realised you can also do

coord = cube.coord('time')
desired_string = str(coord.cell(i).point)

[trexfeathers]

That's cool, I haven't come across coord.cell() before. This still looks like a candidate for a convenience function, you've just made it easier to write!

[rcomer]

Avoiding num2date has the advantage that you can still get something if the coord is not a time coord. Using num2date could give you more flexibility to format the string how you like via the datetime.strftime method.

[trexfeathers]

We've discussed this during a @SciTools/peloton meeting, and decided that having this level of convenience would actually make Iris less helpful, as there would be so many convenience functions as to make Iris' API unreadable.

Therefore closing.