mescla.prep.units.to_meq_per_l

mescla.prep.units.to_meq_per_l(table, on_unknown='raise')

Convert concentrations to milliequivalents per litre: C / equivalent weight.

Only species whose unit is not already meq/L are touched, and only those with a charge can be: an equivalent weight is molar mass divided by charge, so a neutral species has none.

Parameters:

• table (array_like, DataFrame or ChemTable)

• on_unknown ({"raise", "skip", "drop"}, default "raise") –

  What to do about species that cannot be converted – electrical conductivity, silica, isotope ratios, organic compounds.

  "raise" (the default) refuses rather than returning a table that is silently part-converted. "skip" keeps them with their own unit untouched, which is honest because units are tracked per species. "drop" removes them.

Returns:

ChemTable – With the converted species relabelled "meq/L" individually, so a part-converted table describes itself accurately.

Return type:

ChemTable

See also

conversion_factors

the factors this applies, and why a species is refused.

Examples

>>> import mescla as ms
>>> w = ms.WaterChemistry([[40.078, 96.06]], species=["Ca", "SO4"])
>>> to_meq_per_l(w).data.round(3)
array([[2., 2.]])

A species with no equivalent weight is refused rather than passed through:

>>> w = ms.WaterChemistry([[40.078, 500.0]], species=["Ca", "EC"])
>>> to_meq_per_l(w)
ValueError: cannot convert to meq/L: 'EC': not a recognised ion ...
>>> to_meq_per_l(w, on_unknown="skip").units_dict()
{'Ca': 'meq/L', 'EC': 'mg/L'}