API facets reference#
Registry functionality is divided into facet. Each provides classes and functions specific to a particular purpose. They expose at least a Registry, and in certain cases also a Quantity, Unit and other objects.
The default UnitRegistry inherits from all of them.
pint.facets.plain#
Base implementation for registry, units and quantities.
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.facets.plain.AliasDefinition(name: str, aliases: Tuple[str, ...])[source]#
Additional alias(es) for an already existing unit.
- class pint.facets.plain.DefaultsDefinition(group: str | None, system: str | None)[source]#
Directive to store default values.
- class pint.facets.plain.GenericPlainRegistry(*args: Any, **kwargs: Any)[source]#
Base class for all registries.
Capabilities:
Register units, prefixes, and dimensions, and their relations.
Convert between units.
Find dimensionality of a unit.
Parse units with prefix and/or suffix.
Parse expressions.
Parse a definition file.
Allow extending the definition file parser by registering @ directives.
- Parameters:
filename (
str
orNone
) – path of the units definition file to load or line iterable object. Empty to load the default definition file. None to leave the UnitRegistry empty.force_ndarray (
bool
) – convert any input, scalar or not to a numpy.ndarray.force_ndarray_like (
bool
) – convert all inputs other than duck arrays to a numpy.ndarray.on_redefinition (
str
) – action to take in case a unit is redefined: ‘warn’, ‘raise’, ‘ignore’auto_reduce_dimensions – If True, reduce dimensionality on appropriate operations.
autoconvert_to_preferred – If True, converts preferred units on appropriate operations.
preprocessors – list of callables which are iteratively ran on any input expression or unit string
fmt_locale – locale identifier string, used in format_babel
non_int_type (
type
) – numerical type used for non integer values. (Default: float)case_sensitive (
bool
, optional) – Control default case sensitivity of unit parsing. (Default: True)cache_folder (
str
orpathlib.Path
orNone
, optional) – Specify the folder in which cache files are saved and loaded from. If None, the cache is disabled. (default)separate_format_defaults (
bool
, optional) – Separate the default format into magnitude and unit formats as soon as possible. The deprecated default is not to separate. This will change in a future release.
- auto_reduce_dimensions#
Determines if dimensionality should be reduced on appropriate operations.
- autoconvert_to_preferred#
Determines if units will be converted to preffered on appropriate operations.
- case_sensitive#
Default unit case sensitivity
- convert(value: T, src: Quantity | str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit, dst: Quantity | str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit, inplace: bool = False) T [source]#
Convert value from some source to destination units.
- Parameters:
value – value
src (
pint.Quantity
orstr
) – source units.dst (
pint.Quantity
orstr
) – destination units.inplace – (Default value = False)
- Returns:
type
– converted value
- define(definition: str | type) None [source]#
Add unit to the registry.
- Parameters:
definition (
str
orDefinition
) – a dimension, unit or prefix definition.
- get_base_units(input_units: UnitsContainer | str, check_nonmult: bool = True, system=None) tuple[Scalar, UnitT] [source]#
Convert unit or dict of units to the plain units.
If any unit is non multiplicative and check_converter is True, then None is returned as the multiplicative factor.
- Parameters:
- Returns:
Number
,pint.Unit
– multiplicative factor, plain units
- get_dimensionality(input_units: str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit) UnitsContainer [source]#
Convert unit or dict of units or dimensions to a dict of plain dimensions dimensions
- get_name(name_or_alias: str, case_sensitive: bool | None = None) str [source]#
Return the canonical name of a unit.
- get_root_units(input_units: str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit, check_nonmult: bool = True) tuple[float | int | Decimal | Fraction, UnitT] [source]#
Convert unit or dict of units to the root units.
If any unit is non multiplicative and check_converter is True, then None is returned as the multiplicative factor.
- get_symbol(name_or_alias: str, case_sensitive: bool | None = None) str [source]#
Return the preferred alias for a unit.
- is_compatible_with(obj1: Any, obj2: Any, *contexts: str | Context, **ctx_kwargs) bool [source]#
check if the other object is compatible
- Parameters:
obj1, obj2 – The objects to check against each other. Treated as dimensionless if not a Quantity, Unit or str.
*contexts (
str
orpint.Context
) – Contexts to use in the transformation.**ctx_kwargs – Values for the Context/s
- Returns:
- load_definitions(file: Iterable[str] | str | Path, is_resource: bool = False)[source]#
Add units and prefixes defined in a definition text file.
- Parameters:
file – can be a filename or a line iterable.
is_resource – used to indicate that the file is a resource file and therefore should be loaded from the package. (Default value = False)
- mpl_formatter#
sets the formatter used when plotting with matplotlib
- parse_expression(input_string: str, case_sensitive: bool | None = None, **values: Any) QuantityT [source]#
Parse a mathematical expression including units and return a quantity object.
Numerical constants can be specified as keyword arguments and will take precedence over the names defined in the registry.
- Parameters:
input_string
case_sensitive, optional – If true, a case sensitive matching of the unit name will be done in the registry. If false, a case INsensitive matching of the unit name will be done in the registry. (Default value = None, which uses registry setting)
**values – Other string that will be parsed using the Quantity constructor on their corresponding value.
- parse_pattern(input_string: str, pattern: str, case_sensitive: bool | None = None, many: bool = False) list[str] | str | None [source]#
Parse a string with a given regex pattern and returns result.
- Parameters:
input_string
pattern_string – The regex parse string
case_sensitive, optional – If true, a case sensitive matching of the unit name will be done in the registry. If false, a case INsensitive matching of the unit name will be done in the registry. (Default value = None, which uses registry setting)
many, optional – Match many results (Default value = False)
- parse_unit_name(unit_name: str, case_sensitive: bool | None = None) tuple[tuple[str, str, str], ...] [source]#
Parse a unit to identify prefix, unit name and suffix by walking the list of prefix and suffix. In case of equivalent combinations (e.g. (‘kilo’, ‘gram’, ‘’) and (‘’, ‘kilogram’, ‘’), prefer those with prefix.
- parse_units(input_string: str, as_delta: bool | None = None, case_sensitive: bool | None = None) UnitT [source]#
Parse a units expression and returns a UnitContainer with the canonical names.
The expression can only contain products, ratios and powers of units.
- Parameters:
input_string (
str
)as_delta (
bool
orNone
) – if the expression has multiple units, the parser will interpret non multiplicative units as their delta_ counterparts. (Default value = None)case_sensitive (
bool
orNone
) – Control if unit parsing is case sensitive. Defaults to None, which uses the registry’s setting.
- Returns:
- separate_format_defaults#
mode used to fill in the format defaults
- class pint.facets.plain.PlainQuantity(value: MagnitudeT, units: UnitLike | None = None)[source]#
- class pint.facets.plain.PlainQuantity(value: str, units: UnitLike | None = None)
- class pint.facets.plain.PlainQuantity(value: Sequence[ScalarT], units: UnitLike | None = None)
- class pint.facets.plain.PlainQuantity(value: PlainQuantity[Any], units: UnitLike | None = None)
Implements a class to describe a physical quantity: the product of a numerical value and a unit of measurement.
- Parameters:
- check(dimension: str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit) bool [source]#
Return true if the quantity’s dimension matches passed dimension.
- property dimensionality: UnitsContainerT#
- Returns:
dict
– Dimensionality of the PlainQuantity, e.g.{length: 1, time: -1}
- classmethod from_list(quant_list: list[PlainQuantity[MagnitudeT]], units=None) PlainQuantity[MagnitudeT] [source]#
Transforms a list of Quantities into an numpy.array quantity. If no units are specified, the unit of the first element will be used. Same as from_sequence.
If units is not specified and list is empty, the unit cannot be determined and a ValueError is raised.
- classmethod from_sequence(seq: Sequence[PlainQuantity[MagnitudeT]], units=None) PlainQuantity[MagnitudeT] [source]#
Transforms a sequence of Quantities into an numpy.array quantity. If no units are specified, the unit of the first element will be used.
If units is not specified and sequence is empty, the unit cannot be determined and a ValueError is raised.
- is_compatible_with(other: Any, *contexts: str | Context, **ctx_kwargs: Any) bool [source]#
check if the other object is compatible
- Parameters:
other – The object to check. Treated as dimensionless if not a PlainQuantity, Unit or str.
*contexts (
str
orpint.Context
) – Contexts to use in the transformation.**ctx_kwargs – Values for the Context/s
- Returns:
- ito(other: Quantity | str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit | None = None, *contexts, **ctx_kwargs) None [source]#
Inplace rescale to different units.
- Parameters:
other (
pint.PlainQuantity
,str
ordict
) – Destination units. (Default value = None)*contexts (
str
orpint.Context
) – Contexts to use in the transformation.**ctx_kwargs – Values for the Context/s
- ito_preferred(preferred_units: list[UnitLike] | None = None) PlainQuantity #
Return Quantity converted to a unit composed of the preferred units.
Examples
>>> import pint >>> ureg = pint.UnitRegistry() >>> (1*ureg.acre).to_preferred([ureg.meters]) <Quantity(4046.87261, 'meter ** 2')> >>> (1*(ureg.force_pound*ureg.m)).to_preferred([ureg.W]) <Quantity(4.44822162, 'watt * second')>
- ito_reduced_units() None #
Return PlainQuantity scaled in place to reduced units, i.e. one unit per dimension. This will not reduce compound units (e.g., ‘J/kg’ will not be reduced to m**2/s**2), nor can it make use of contexts at this time.
- property m: MagnitudeT#
PlainQuantity’s magnitude. Short form for magnitude
- property magnitude: MagnitudeT#
PlainQuantity’s magnitude. Long form for m
- to(other: Quantity | str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit | None = None, *contexts, **ctx_kwargs) PlainQuantity [source]#
Return PlainQuantity rescaled to different units.
- Parameters:
other (
pint.PlainQuantity
,str
ordict
) – destination units. (Default value = None)*contexts (
str
orpint.Context
) – Contexts to use in the transformation.**ctx_kwargs – Values for the Context/s
- Returns:
pint.PlainQuantity
- to_base_units() PlainQuantity[MagnitudeT] [source]#
Return PlainQuantity rescaled to plain units.
- to_compact(unit: UnitsContainer | None = None) PlainQuantity #
“Return PlainQuantity rescaled to compact, human-readable units.
To get output in terms of a different unit, use the unit parameter.
Examples
>>> import pint >>> ureg = pint.UnitRegistry() >>> (200e-9*ureg.s).to_compact() <Quantity(200.0, 'nanosecond')> >>> (1e-2*ureg('kg m/s^2')).to_compact('N') <Quantity(10.0, 'millinewton')>
- to_preferred(preferred_units: list[UnitLike] | None = None) PlainQuantity #
Return Quantity converted to a unit composed of the preferred units.
Examples
>>> import pint >>> ureg = pint.UnitRegistry() >>> (1*ureg.acre).to_preferred([ureg.meters]) <Quantity(4046.87261, 'meter ** 2')> >>> (1*(ureg.force_pound*ureg.m)).to_preferred([ureg.W]) <Quantity(4.44822162, 'watt * second')>
- to_reduced_units() PlainQuantity #
Return PlainQuantity scaled in place to reduced units, i.e. one unit per dimension. This will not reduce compound units (intentionally), nor can it make use of contexts at this time.
- to_root_units() PlainQuantity[MagnitudeT] [source]#
Return PlainQuantity rescaled to root units.
- class pint.facets.plain.PlainUnit(*args, **kwargs)[source]#
Implements a class to describe a unit supporting math operations.
- property dimensionality: UnitsContainer#
- Returns:
dict
– Dimensionality of the PlainUnit, e.g.{length: 1, time: -1}
- from_(value, strict=True, name='value')[source]#
Converts a numerical value or quantity to this unit
- Parameters:
value – a Quantity (or numerical value if strict=False) to convert
strict – boolean to indicate that only quantities are accepted (Default value = True)
name – descriptive name to use if an exception occurs (Default value = “value”)
- Returns:
type
– The converted value as this unit
- is_compatible_with(other: Any, *contexts: str | Context, **ctx_kwargs: Any) bool [source]#
check if the other object is compatible
- Parameters:
other – The object to check. Treated as dimensionless if not a Quantity, PlainUnit or str.
*contexts (
str
orpint.Context
) – Contexts to use in the transformation.**ctx_kwargs – Values for the Context/s
- Returns:
- m_from(value, strict=True, name='value')[source]#
Converts a numerical value or quantity to this unit, then returns the magnitude of the converted value
- Parameters:
value – a Quantity (or numerical value if strict=False) to convert
strict – boolean to indicate that only quantities are accepted (Default value = True)
name – descriptive name to use if an exception occurs (Default value = “value”)
- Returns:
type
– The magnitude of the converted value
- class pint.facets.plain.PrefixDefinition(name: str, value: Number, defined_symbol: str | None = '', aliases: Tuple[str, ...] = ())[source]#
Definition of a prefix.
- class pint.facets.plain.ScaleConverter(scale: float)[source]#
A linear transformation without offset.
- class pint.facets.plain.UnitDefinition(name: str, defined_symbol: str | None, aliases: tuple[str, ...], converter: Converter | None, reference: UnitsContainer | None)[source]#
Definition of a unit.
- reference: UnitsContainer | None#
Reference units.
pint.facets.nonmultiplicative#
Adds pint the capability to handle nonmultiplicative units: - offset - logarithmic
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.facets.nonmultiplicative.GenericNonMultiplicativeRegistry(*args: Any, **kwargs: Any)[source]#
Handle of non multiplicative units (e.g. Temperature).
Capabilities: - Register non-multiplicative units and their relations. - Convert between non-multiplicative units.
- Parameters:
- default_as_delta#
When performing a multiplication of units, interpret non-multiplicative units as their delta counterparts.
pint.delegates.formatter#
Easy to replace and extend string formatting.
See pint.delegates.formatter.plain.DefaultFormatter for a description of a formatter.
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.delegates.formatter.Formatter(registry: UnitRegistry | None = None)[source]#
Default Pint Formatter
pint.facets.numpy#
Adds pint the capability to interoperate with NumPy
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
pint.facets.dask#
Adds pint the capability to interoperate with Dask
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.facets.dask.DaskQuantity(value: MagnitudeT, units: UnitLike | None = None)[source]#
- class pint.facets.dask.DaskQuantity(value: str, units: UnitLike | None = None)
- class pint.facets.dask.DaskQuantity(value: Sequence[ScalarT], units: UnitLike | None = None)
- class pint.facets.dask.DaskQuantity(value: PlainQuantity[Any], units: UnitLike | None = None)
- compute(**kwargs)[source]#
Compute the Dask array wrapped by pint.PlainQuantity.
- Parameters:
**kwargs (
dict
) – Any keyword arguments to pass todask.compute
.- Returns:
pint.PlainQuantity
– A pint.PlainQuantity wrapped numpy array.
pint.facets.measurement#
Adds pint the capability to handle measurements (quantities with uncertainties).
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.facets.measurement.MeasurementQuantity(value: MagnitudeT, units: UnitLike | None = None)[source]#
- class pint.facets.measurement.MeasurementQuantity(value: str, units: UnitLike | None = None)
- class pint.facets.measurement.MeasurementQuantity(value: Sequence[ScalarT], units: UnitLike | None = None)
- class pint.facets.measurement.MeasurementQuantity(value: PlainQuantity[Any], units: UnitLike | None = None)
pint.facets.group#
Adds pint the capability to group units.
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.facets.group.GenericGroupRegistry(*args: Any, **kwargs: Any)[source]#
Handle of Groups.
Group units
Capabilities: - Register groups. - Parse @group directive.
- class pint.facets.group.GroupDefinition(name: str, using_group_names: tuple[str, ...], definitions: tuple[UnitDefinition, ...])[source]#
Definition of a group.
- definitions: tuple[UnitDefinition, ...]#
definitions for the units existing within the group
- class pint.facets.group.GroupQuantity(value: MagnitudeT, units: UnitLike | None = None)[source]#
- class pint.facets.group.GroupQuantity(value: str, units: UnitLike | None = None)
- class pint.facets.group.GroupQuantity(value: Sequence[ScalarT], units: UnitLike | None = None)
- class pint.facets.group.GroupQuantity(value: PlainQuantity[Any], units: UnitLike | None = None)
pint.facets.system#
Adds pint the capability to system of units.
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.facets.system.GenericSystemRegistry(*args: Any, **kwargs: Any)[source]#
Handle of Systems.
Conversion between units with different dimensions according to previously established relations (contexts). (e.g. in the spectroscopy, conversion between frequency and energy is possible)
Capabilities:
Register systems.
List systems
Get or get the default system.
Parse @group directive.
- get_base_units(input_units: str | dict[str, float | int | Decimal | Fraction] | UnitsContainer | Unit | Quantity, check_nonmult: bool = True, system: str | System | None = None) tuple[Number, Unit] [source]#
Convert unit or dict of units to the plain units.
If any unit is non multiplicative and check_converter is True, then None is returned as the multiplicative factor.
Unlike PlainRegistry, in this registry root_units might be different from base_units
- Parameters:
- Returns:
type
– multiplicative factor, plain units
- class pint.facets.system.SystemDefinition(name: str, using_group_names: tuple[str, ...], rules: tuple[BaseUnitRule, ...])[source]#
Definition of a System.
pint.facets.context#
Adds pint the capability to contexts: predefined conversions between incompatible dimensions.
- copyright:
2022 by Pint Authors, see AUTHORS for more details.
- license:
BSD, see LICENSE for more details.
- class pint.facets.context.ContextDefinition(name: str, aliases: tuple[str, ...], defaults: dict[str, Number], relations: tuple[Relation, ...], redefinitions: tuple[UnitDefinition, ...])[source]#
Definition of a Context
- class pint.facets.context.GenericContextRegistry(*args: Any, **kwargs: Any)[source]#
Handle of Contexts.
Conversion between units with different dimensions according to previously established relations (contexts). (e.g. in the spectroscopy, conversion between frequency and energy is possible)
Capabilities:
Register contexts.
Enable and disable contexts.
Parse @context directive.
- add_context(context: Context | ContextDefinition) None [source]#
Add a context object to the registry.
The context will be accessible by its name and aliases.
Notice that this method will NOT enable the context; see
enable_contexts()
.
- context(*names: str, **kwargs: Any) Generator[GenericContextRegistry[QuantityT, UnitT], None, None] [source]#
Used as a context manager, this function enables to activate a context which is removed after usage.
- Parameters:
*names (
name(s)
ofthe context(s).
)**kwargs (
keyword arguments for the contexts.
)
Examples
Context can be called by their name:
>>> import pint.facets.context.objects >>> import pint >>> ureg = pint.UnitRegistry() >>> ureg.add_context(pint.facets.context.objects.Context('one')) >>> ureg.add_context(pint.facets.context.objects.Context('two')) >>> with ureg.context('one'): ... pass
If a context has an argument, you can specify its value as a keyword argument:
>>> with ureg.context('one', n=1): ... pass
Multiple contexts can be entered in single call:
>>> with ureg.context('one', 'two', n=1): ... pass
Or nested allowing you to give different values to the same keyword argument:
>>> with ureg.context('one', n=1): ... with ureg.context('two', n=2): ... pass
A nested context inherits the defaults from the containing context:
>>> with ureg.context('one', n=1): ... # Here n takes the value of the outer context ... with ureg.context('two'): ... pass
- disable_contexts(n: int | None = None) None [source]#
Disable the last n enabled contexts.
- Parameters:
n (
int
) – Number of contexts to disable. Default: disable all contexts.
- enable_contexts(*names_or_contexts: str | Context, **kwargs: Any) None [source]#
Enable contexts provided by name or by object.
- Parameters:
*names_or_contexts – one or more contexts or context names/aliases
**kwargs – keyword arguments for the context(s)
Examples
See
context()
- remove_context(name_or_alias: str) Context [source]#
Remove a context from the registry and return it.
Notice that this methods will not disable the context; see
disable_contexts()
.
- with_context(name: str, **kwargs: Any) Callable[[F], F] [source]#
Decorator to wrap a function call in a Pint context.
Use it to ensure that a certain context is active when calling a function.
- Parameters:
name – name of the context.
**kwargs – keyword arguments for the context
- Returns:
callable (
the wrapped function.
)
Examples
>>> @ureg.with_context('sp') ... def my_cool_fun(wavelength): ... print('This wavelength is equivalent to: %s', wavelength.to('terahertz'))