def modify(self, symbol, base_value):
"""
Change the base value of a unit symbol. Useful for adjusting code
units after parsing parameters.
Parameters
----------
symbol : str
The name of the symbol to modify
base_value : float
The new base_value for the symbol.
"""
self._unit_system_id = None
if symbol not in self.lut:
raise SymbolNotFoundError(
"Tried to modify the symbol '%s', but it does not exist "
"in this registry." % symbol
)
if hasattr(base_value, "in_base"):
new_dimensions = base_value.units.dimensions
base_value = base_value.in_base("mks")
base_value = base_value.value
else:
new_dimensions = self.lut[symbol][1]
self.lut[symbol] = (float(base_value), new_dimensions) + self.lut[symbol][2:]
def __getitem__(self, key):
try:
ret = self.lut[key]
except KeyError:
raise SymbolNotFoundError(
"The symbol '%s' does not exist in this registry." % key)
return ret
def __getitem__(self, key):
try:
ret = self.lut[str(key)]
except KeyError:
try:
_lookup_unit_symbol(str(key), self.lut)
ret = self.lut[str(key)]
except UnitParseError:
raise SymbolNotFoundError(
"The symbol '%s' does not exist in this registry." % key)
return ret
def remove(self, symbol):
"""
Remove the entry for the unit matching `symbol`.
"""
self._unit_system_id = None
if symbol not in self.lut:
raise SymbolNotFoundError(
"Tried to remove the symbol '%s', but it does not exist "
"in this registry." % symbol)
del self.lut[symbol]