Log to the console rather than print()

[lochhh]

I assume @VascoSch92 meant that this should be logged to the console rather than printed (e.g. so verbosity can be changed by third parties).

Originally posted by @adamltyson in #209 (comment)

When reporting number of NaNs in filtering, we currently use a print statement to print this to the console, whilst also logging this to the log attribute of a DataArray.

[adamltyson]

In general (but not necessarily absolutely) I think movement should avoid printing things to the console. This could get annoying if a user has a script that repeats a process many times. It should be possible for the user to configure what gets printed using the logging module.

[niksirbi]

I agree on this principle.

In this case, it's very useful to quickly see the number of NaNs before/after an operation. Given the new utility functions that @lochhh has nicely refactored into the utils/reports.py module, what would be our recommended way for viewing the report (e.g. in a notebook cell)?

One way would be for report_nan_values() to also return the report as a string, so one can do print(report_nan_values(ds)). Or are there easier ways of doing this by configuring the logger to show INFO in the cell output?

[adamltyson]

I think I wouldn't expect to use logging to see this in a notebook necessarily, but an explicit call, so something like print(report_nan_values(ds))

[niksirbi]

I agree, so perhaps we should modify that function in #209 to return the string?

[niksirbi]

Thanks @lochhh ! We can close this issue once I approve #209 and we merge it.