PlasmaCalcs.tools.xarray_tools.xarray_misc.xarray_vars_lookup_with_defaults

PlasmaCalcs.tools.xarray_tools.xarray_misc.xarray_vars_lookup_with_defaults(ds, provided, lookup={}, defaults={})

return dict of {key from lookup: value for that key}.

provided: dict of {key: None, str, or other value}

provided values or lookup instructions for each key.

None –> use instructions from lookup if key in lookup,

else value from defaults if key in defaults.

str –> varname; result uses ds[varname]. (crash if not possible.)

callable –> f of one arg; result uses f(ds).

other value –> result uses this value directly.

lookup: dict of {key: None, str, or list of str}

‘default’ lookup instructions. Used when provided[key] is None.

defaults: dict of {key: value or callable}

default values for each key.

Used when provided[key] is None and ds[lookup[key]] not found.

callable –> called with ds as arg to get value.

Examples:

xarray_vars_lookup_with_defaults(ds, {}, {‘n’: None}, {‘n’: 100})

# {‘n’: ds[‘n’]} if ds[‘n’] exists, else {‘n’: 100}

xarray_vars_lookup_with_defaults(ds, {}, {‘n’: ‘var1’}, {‘n’: lambda ds: ds.size})

# {‘n’: ds[‘var1’]} if ds[‘var1’] exists, else {‘n’: ds.size}

xarray_vars_lookup_with_defaults(ds, {‘n’: ‘var1’}, {‘n’: ‘var2’}, {‘n’: 7})

# {‘n’: ds[‘var1’]} if ds[‘var1’] exists, else crash.

# (lookup & defaults are fully ignored, if non-None value in provided.)