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- from __future__ import annotations
- import decimal
- from typing import Literal
- from babel.core import Locale
- from babel.numbers import LC_NUMERIC, format_decimal
- class UnknownUnitError(ValueError):
- def __init__(self, unit: str, locale: Locale) -> None:
- ValueError.__init__(self, f"{unit} is not a known unit in {locale}")
- def get_unit_name(
- measurement_unit: str,
- length: Literal['short', 'long', 'narrow'] = 'long',
- locale: Locale | str | None = None,
- ) -> str | None:
- """
- Get the display name for a measurement unit in the given locale.
- >>> get_unit_name("radian", locale="en")
- 'radians'
- Unknown units will raise exceptions:
- >>> get_unit_name("battery", locale="fi")
- Traceback (most recent call last):
- ...
- UnknownUnitError: battery/long is not a known unit/length in fi
- :param measurement_unit: the code of a measurement unit.
- Known units can be found in the CLDR Unit Validity XML file:
- https://unicode.org/repos/cldr/tags/latest/common/validity/unit.xml
- :param length: "short", "long" or "narrow"
- :param locale: the `Locale` object or locale identifier. Defaults to the system numeric locale.
- :return: The unit display name, or None.
- """
- locale = Locale.parse(locale or LC_NUMERIC)
- unit = _find_unit_pattern(measurement_unit, locale=locale)
- if not unit:
- raise UnknownUnitError(unit=measurement_unit, locale=locale)
- return locale.unit_display_names.get(unit, {}).get(length)
- def _find_unit_pattern(unit_id: str, locale: Locale | str | None = None) -> str | None:
- """
- Expand a unit into a qualified form.
- Known units can be found in the CLDR Unit Validity XML file:
- https://unicode.org/repos/cldr/tags/latest/common/validity/unit.xml
- >>> _find_unit_pattern("radian", locale="en")
- 'angle-radian'
- Unknown values will return None.
- >>> _find_unit_pattern("horse", locale="en")
- :param unit_id: the code of a measurement unit.
- :return: A key to the `unit_patterns` mapping, or None.
- """
- locale = Locale.parse(locale or LC_NUMERIC)
- unit_patterns: dict[str, str] = locale._data["unit_patterns"]
- if unit_id in unit_patterns:
- return unit_id
- for unit_pattern in sorted(unit_patterns, key=len):
- if unit_pattern.endswith(unit_id):
- return unit_pattern
- return None
- def format_unit(
- value: str | float | decimal.Decimal,
- measurement_unit: str,
- length: Literal['short', 'long', 'narrow'] = 'long',
- format: str | None = None,
- locale: Locale | str | None = None,
- *,
- numbering_system: Literal["default"] | str = "latn",
- ) -> str:
- """Format a value of a given unit.
- Values are formatted according to the locale's usual pluralization rules
- and number formats.
- >>> format_unit(12, 'length-meter', locale='ro_RO')
- u'12 metri'
- >>> format_unit(15.5, 'length-mile', locale='fi_FI')
- u'15,5 mailia'
- >>> format_unit(1200, 'pressure-millimeter-ofhg', locale='nb')
- u'1\\xa0200 millimeter kvikks\\xf8lv'
- >>> format_unit(270, 'ton', locale='en')
- u'270 tons'
- >>> format_unit(1234.5, 'kilogram', locale='ar_EG', numbering_system='default')
- u'1٬234٫5 كيلوغرام'
- Number formats may be overridden with the ``format`` parameter.
- >>> import decimal
- >>> format_unit(decimal.Decimal("-42.774"), 'temperature-celsius', 'short', format='#.0', locale='fr')
- u'-42,8\\u202f\\xb0C'
- The locale's usual pluralization rules are respected.
- >>> format_unit(1, 'length-meter', locale='ro_RO')
- u'1 metru'
- >>> format_unit(0, 'length-mile', locale='cy')
- u'0 mi'
- >>> format_unit(1, 'length-mile', locale='cy')
- u'1 filltir'
- >>> format_unit(3, 'length-mile', locale='cy')
- u'3 milltir'
- >>> format_unit(15, 'length-horse', locale='fi')
- Traceback (most recent call last):
- ...
- UnknownUnitError: length-horse is not a known unit in fi
- .. versionadded:: 2.2.0
- :param value: the value to format. If this is a string, no number formatting will be attempted.
- :param measurement_unit: the code of a measurement unit.
- Known units can be found in the CLDR Unit Validity XML file:
- https://unicode.org/repos/cldr/tags/latest/common/validity/unit.xml
- :param length: "short", "long" or "narrow"
- :param format: An optional format, as accepted by `format_decimal`.
- :param locale: the `Locale` object or locale identifier. Defaults to the system numeric locale.
- :param numbering_system: The numbering system used for formatting number symbols. Defaults to "latn".
- The special value "default" will use the default numbering system of the locale.
- :raise `UnsupportedNumberingSystemError`: If the numbering system is not supported by the locale.
- """
- locale = Locale.parse(locale or LC_NUMERIC)
- q_unit = _find_unit_pattern(measurement_unit, locale=locale)
- if not q_unit:
- raise UnknownUnitError(unit=measurement_unit, locale=locale)
- unit_patterns = locale._data["unit_patterns"][q_unit].get(length, {})
- if isinstance(value, str): # Assume the value is a preformatted singular.
- formatted_value = value
- plural_form = "one"
- else:
- formatted_value = format_decimal(value, format, locale, numbering_system=numbering_system)
- plural_form = locale.plural_form(value)
- if plural_form in unit_patterns:
- return unit_patterns[plural_form].format(formatted_value)
- # Fall back to a somewhat bad representation.
- # nb: This is marked as no-cover, as the current CLDR seemingly has no way for this to happen.
- fallback_name = get_unit_name(measurement_unit, length=length, locale=locale) # pragma: no cover
- return f"{formatted_value} {fallback_name or measurement_unit}" # pragma: no cover
- def _find_compound_unit(
- numerator_unit: str,
- denominator_unit: str,
- locale: Locale | str | None = None,
- ) -> str | None:
- """
- Find a predefined compound unit pattern.
- Used internally by format_compound_unit.
- >>> _find_compound_unit("kilometer", "hour", locale="en")
- 'speed-kilometer-per-hour'
- >>> _find_compound_unit("mile", "gallon", locale="en")
- 'consumption-mile-per-gallon'
- If no predefined compound pattern can be found, `None` is returned.
- >>> _find_compound_unit("gallon", "mile", locale="en")
- >>> _find_compound_unit("horse", "purple", locale="en")
- :param numerator_unit: The numerator unit's identifier
- :param denominator_unit: The denominator unit's identifier
- :param locale: the `Locale` object or locale identifier. Defaults to the system numeric locale.
- :return: A key to the `unit_patterns` mapping, or None.
- :rtype: str|None
- """
- locale = Locale.parse(locale or LC_NUMERIC)
- # Qualify the numerator and denominator units. This will turn possibly partial
- # units like "kilometer" or "hour" into actual units like "length-kilometer" and
- # "duration-hour".
- resolved_numerator_unit = _find_unit_pattern(numerator_unit, locale=locale)
- resolved_denominator_unit = _find_unit_pattern(denominator_unit, locale=locale)
- # If either was not found, we can't possibly build a suitable compound unit either.
- if not (resolved_numerator_unit and resolved_denominator_unit):
- return None
- # Since compound units are named "speed-kilometer-per-hour", we'll have to slice off
- # the quantities (i.e. "length", "duration") from both qualified units.
- bare_numerator_unit = resolved_numerator_unit.split("-", 1)[-1]
- bare_denominator_unit = resolved_denominator_unit.split("-", 1)[-1]
- # Now we can try and rebuild a compound unit specifier, then qualify it:
- return _find_unit_pattern(f"{bare_numerator_unit}-per-{bare_denominator_unit}", locale=locale)
- def format_compound_unit(
- numerator_value: str | float | decimal.Decimal,
- numerator_unit: str | None = None,
- denominator_value: str | float | decimal.Decimal = 1,
- denominator_unit: str | None = None,
- length: Literal["short", "long", "narrow"] = "long",
- format: str | None = None,
- locale: Locale | str | None = None,
- *,
- numbering_system: Literal["default"] | str = "latn",
- ) -> str | None:
- """
- Format a compound number value, i.e. "kilometers per hour" or similar.
- Both unit specifiers are optional to allow for formatting of arbitrary values still according
- to the locale's general "per" formatting specifier.
- >>> format_compound_unit(7, denominator_value=11, length="short", locale="pt")
- '7/11'
- >>> format_compound_unit(150, "kilometer", denominator_unit="hour", locale="sv")
- '150 kilometer per timme'
- >>> format_compound_unit(150, "kilowatt", denominator_unit="year", locale="fi")
- '150 kilowattia / vuosi'
- >>> format_compound_unit(32.5, "ton", 15, denominator_unit="hour", locale="en")
- '32.5 tons per 15 hours'
- >>> format_compound_unit(1234.5, "ton", 15, denominator_unit="hour", locale="ar_EG", numbering_system="arab")
- '1٬234٫5 طن لكل 15 ساعة'
- >>> format_compound_unit(160, denominator_unit="square-meter", locale="fr")
- '160 par m\\xe8tre carr\\xe9'
- >>> format_compound_unit(4, "meter", "ratakisko", length="short", locale="fi")
- '4 m/ratakisko'
- >>> format_compound_unit(35, "minute", denominator_unit="nautical-mile", locale="sv")
- '35 minuter per nautisk mil'
- >>> from babel.numbers import format_currency
- >>> format_compound_unit(format_currency(35, "JPY", locale="de"), denominator_unit="liter", locale="de")
- '35\\xa0\\xa5 pro Liter'
- See https://www.unicode.org/reports/tr35/tr35-general.html#perUnitPatterns
- :param numerator_value: The numerator value. This may be a string,
- in which case it is considered preformatted and the unit is ignored.
- :param numerator_unit: The numerator unit. See `format_unit`.
- :param denominator_value: The denominator value. This may be a string,
- in which case it is considered preformatted and the unit is ignored.
- :param denominator_unit: The denominator unit. See `format_unit`.
- :param length: The formatting length. "short", "long" or "narrow"
- :param format: An optional format, as accepted by `format_decimal`.
- :param locale: the `Locale` object or locale identifier. Defaults to the system numeric locale.
- :param numbering_system: The numbering system used for formatting number symbols. Defaults to "latn".
- The special value "default" will use the default numbering system of the locale.
- :return: A formatted compound value.
- :raise `UnsupportedNumberingSystemError`: If the numbering system is not supported by the locale.
- """
- locale = Locale.parse(locale or LC_NUMERIC)
- # Look for a specific compound unit first...
- if numerator_unit and denominator_unit and denominator_value == 1:
- compound_unit = _find_compound_unit(numerator_unit, denominator_unit, locale=locale)
- if compound_unit:
- return format_unit(
- numerator_value,
- compound_unit,
- length=length,
- format=format,
- locale=locale,
- numbering_system=numbering_system,
- )
- # ... failing that, construct one "by hand".
- if isinstance(numerator_value, str): # Numerator is preformatted
- formatted_numerator = numerator_value
- elif numerator_unit: # Numerator has unit
- formatted_numerator = format_unit(
- numerator_value,
- numerator_unit,
- length=length,
- format=format,
- locale=locale,
- numbering_system=numbering_system,
- )
- else: # Unitless numerator
- formatted_numerator = format_decimal(
- numerator_value,
- format=format,
- locale=locale,
- numbering_system=numbering_system,
- )
- if isinstance(denominator_value, str): # Denominator is preformatted
- formatted_denominator = denominator_value
- elif denominator_unit: # Denominator has unit
- if denominator_value == 1: # support perUnitPatterns when the denominator is 1
- denominator_unit = _find_unit_pattern(denominator_unit, locale=locale)
- per_pattern = locale._data["unit_patterns"].get(denominator_unit, {}).get(length, {}).get("per")
- if per_pattern:
- return per_pattern.format(formatted_numerator)
- # See TR-35's per-unit pattern algorithm, point 3.2.
- # For denominator 1, we replace the value to be formatted with the empty string;
- # this will make `format_unit` return " second" instead of "1 second".
- denominator_value = ""
- formatted_denominator = format_unit(
- denominator_value,
- measurement_unit=(denominator_unit or ""),
- length=length,
- format=format,
- locale=locale,
- numbering_system=numbering_system,
- ).strip()
- else: # Bare denominator
- formatted_denominator = format_decimal(
- denominator_value,
- format=format,
- locale=locale,
- numbering_system=numbering_system,
- )
- # TODO: this doesn't support "compound_variations" (or "prefix"), and will fall back to the "x/y" representation
- per_pattern = locale._data["compound_unit_patterns"].get("per", {}).get(length, {}).get("compound", "{0}/{1}")
- return per_pattern.format(formatted_numerator, formatted_denominator)
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