"""Value and quantity conversion."""
import logging
import re
import numpy as np
from astropy import units as u
import simtools.utils.general as gen
_logger = logging.getLogger(__name__)
[docs]
def get_value_unit_type(value, unit_str=None):
"""
Get the value, unit and type of a value.
The value is stripped of its unit and the unit is returned
in its string form (i.e., to_string()).
The type is returned as a string representation of the type.
For example, for a string, it returns 'str' rather than '<class 'str'>'.
An additional unit string can be given and the return value is converted to this units.
Note that Quantities are always floats, even if the original value is represented as an int.
Parameters
----------
value: str, int, float, bool, u.Quantity
Value to be parsed.
unit_str: str
Unit to be used for the value.
Returns
-------
type of value, str, str
Value, unit in string representation (to_string())),
and string representation of the type of the value.
"""
base_unit = None
if isinstance(value, str | u.Quantity):
try:
_quantity_value = u.Quantity(value)
base_value = _quantity_value.value
base_type = extract_type_of_value(base_value)
if _quantity_value.unit.to_string() != "":
base_unit = _quantity_value.unit.to_string()
try: # handle case of e.g., "0 0" and avoid unit.scale
float(base_unit)
base_value = value
base_type = "str"
base_unit = None
except ValueError:
pass
# ValueError: covers strings of type "5 not a unit"
except (TypeError, ValueError):
base_value = value
base_type = "str"
else:
base_value = value
base_type = extract_type_of_value(base_value)
if unit_str is not None:
try:
base_value = base_value * u.Unit(base_unit).to(u.Unit(unit_str))
except u.UnitConversionError:
_logger.error(f"Cannot convert {base_unit} to {unit_str}.")
raise
except TypeError:
pass
base_unit = unit_str
return base_value, base_unit, base_type
[docs]
def split_value_and_unit(value):
"""
Split a value into its value and unit.
Takes into account the case where the value is a Quantity, a number,
or a simtools-type string encoding a list of values and units.
Parameters
----------
value: str, int, float, bool, u.Quantity
Value to be parsed.
Returns
-------
value, str
Value and units as (value, unit), or lists of values and unites
"""
if isinstance(value, u.Quantity):
return _split_value_is_quantity(value)
if isinstance(value, str):
return _split_value_is_string(value)
if isinstance(value, list | np.ndarray):
return _split_value_is_list(value)
return value, None
def _split_value_is_quantity(value):
"""Split value and unit for an astropy Quantity."""
if isinstance(value.value, list | np.ndarray): # type [100.0, 200] * u.m,
return list(value.value), [str(value.unit)] * len(value)
return value.value, str(value.unit)
def _split_value_is_string(value):
"""Split vale and unit for a string."""
if value.isdigit(): # single integer value
return int(value), None
try: # single value with/without unit
return u.Quantity(value).value, str(u.Quantity(value).unit)
except ValueError:
return _split_value_is_list(gen.convert_string_to_list(value))
except TypeError: # string value (not numerical)
return value, None
def _split_value_is_list(value):
"""Split value and unit for a list."""
value_list = []
unit_list = []
for item in value:
_value, _unit = split_value_and_unit(item)
value_list.append(_value)
if isinstance(_unit, str):
unit_list.append(_unit)
else:
unit_list.append(None)
return value_list, unit_list
[docs]
def get_value_as_quantity(value, unit):
"""
Get a value as a Quantity with a given unit. If value is a Quantity, convert to the given unit.
Parameters
----------
value:
value to get a unit. It can be a float, int, or a Quantity (convertible to 'unit').
unit: astropy.units.Unit
Unit to apply to 'quantity'.
Returns
-------
astropy.units.Quantity
Quantity of value 'quantity' and unit 'unit'.
Raises
------
u.UnitConversionError
If the value cannot be converted to the given unit.
"""
if isinstance(value, u.Quantity):
try:
return value.to(unit)
except u.UnitConversionError:
_logger.error(f"Cannot convert {value.unit} to {unit}.")
raise
return value * unit
