xarray.DataArray.pr.quantify

DataArray.pr.quantify(**kwargs)

Attaches units to the DataArray.

Units can be specified as a pint.Unit or as a string. If no units are specified then the units will be parsed from the ‘units’ entry of the DataArray’s .attrs. Will raise a ValueError if the DataArray already contains a unit-aware array.

This function is a wrapper for pint_xarrays function with the same name, which uses the primap2 unit registry. Calling da.pr.quantify() is therefore equivalent to calling da.pint.quantify(unit_registry=primap2.ureg)

Note

Be aware that unless you’re using dask this will load the data into memory. To avoid that, consider converting to dask first (e.g. using chunk).

As units in dimension coordinates are not supported until xarray changes the way it implements indexes, these units will be set as attributes.

Parameters:

unitsunit-like or mapping of hashable to unit-like, optional

Physical units to use for this DataArray. If a str or pint.Unit, will be used as the DataArray’s units. If a dict-like, it should map a variable name to the desired unit (use the DataArray’s name to refer to its data). If not provided, will try to read them from DataArray.attrs['units'] using pint’s parser. The "units" attribute will be removed from all variables except from dimension coordinates.

**unit_kwargs

Keyword argument form of units.

Returns:

quantifiedDataArray

DataArray whose wrapped array data will now be a Quantity array with the specified units.

Examples

>>> da = xr.DataArray(
...     data=[0.4, 0.9, 1.7, 4.8, 3.2, 9.1],
...     dims=["wavelength"],
...     coords={"wavelength": [1e-4, 2e-4, 4e-4, 6e-4, 1e-3, 2e-3]},
... )
>>> da.pint.quantify(units="Hz")
<xarray.DataArray (wavelength: 6)>
<Quantity([0.4 0.9 1.7 4.8 3.2 9.1], 'hertz')>
Coordinates:
  * wavelength  (wavelength) float64 0.0001 0.0002 0.0004 0.0006 0.001 0.002