searx.wikidata_units Namespace Reference

Classes
class	Beaufort

Functions
float	convert_from_si (str si_name, str symbol, float|int value)
float	convert_to_si (str si_name, str symbol, float|int value)
	units_by_si_name (si_name)
	symbol_to_si ()
	fetch_units ()

Variables
list	__all__ = ["convert_from_si", "convert_to_si", "symbol_to_si"]
list	ADDITIONAL_UNITS
dict	ALIAS_SYMBOLS
list	SYMBOL_TO_SI = []
dict	UNITS_BY_SI_NAME = {}
int	pos_symbol = 0
int	pos_si_name = 1
int	pos_from_si = 2
int	pos_to_si = 3
str	SARQL_REQUEST

Detailed Description

Unit conversion on the basis of `SPARQL/WIKIDATA Precision, Units and
Coordinates`_

.. _SPARQL/WIKIDATA Precision, Units and Coordinates:
   https://en.wikibooks.org/wiki/SPARQL/WIKIDATA_Precision,_Units_and_Coordinates#Quantities

Function Documentation

convert_from_si()

float searx.wikidata_units.convert_from_si	(	str	si_name,
		str	symbol,
		float | int	value )

Definition at line 120 of file wikidata_units.py.

def convert_from_si(si_name: str, symbol: str, value: float | int) -> float:
    from_si = units_by_si_name(si_name)[symbol][pos_from_si]
    if isinstance(from_si, (float, int)):
        value = float(value) * from_si
    else:
        value = from_si(float(value))
    return value
 
 

References units_by_si_name().

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convert_to_si()

float searx.wikidata_units.convert_to_si	(	str	si_name,
		str	symbol,
		float | int	value )

Definition at line 129 of file wikidata_units.py.

def convert_to_si(si_name: str, symbol: str, value: float | int) -> float:
    to_si = units_by_si_name(si_name)[symbol][pos_to_si]
    if isinstance(to_si, (float, int)):
        value = float(value) * to_si
    else:
        value = to_si(float(value))
    return value
 
 

References units_by_si_name().

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fetch_units()

searx.wikidata_units.fetch_units

(

)

Fetch units from Wikidata.  Function is used to update persistence of
:py:obj:`searx.data.WIKIDATA_UNITS`.

Definition at line 270 of file wikidata_units.py.

def fetch_units():
    """Fetch units from Wikidata.  Function is used to update persistence of
    :py:obj:`searx.data.WIKIDATA_UNITS`."""
 
    results = collections.OrderedDict()
    response = wikidata.send_wikidata_query(SARQL_REQUEST)
    for unit in response['results']['bindings']:
 
        symbol = unit['symbol']['value']
        name = unit['item']['value'].rsplit('/', 1)[1]
        si_name = unit.get('tosiUnit', {}).get('value', '')
        if si_name:
            si_name = si_name.rsplit('/', 1)[1]
 
        to_si_factor = unit.get('tosi', {}).get('value', '')
        if name not in results:
            # ignore duplicate: always use the first one
            results[name] = {
                'symbol': symbol,
                'si_name': si_name if si_name else None,
                'to_si_factor': float(to_si_factor) if to_si_factor else None,
            }
    return results

symbol_to_si()

searx.wikidata_units.symbol_to_si

(

)

Generates a list of tuples, each tuple is a measure unit and the fields
in the tuple are:

0. Symbol of the measure unit (e.g. 'mi' for measure unit 'miles' Q253276)

1. SI name of the measure unit (e.g. Q11573 for SI unit 'metre')

2. Factor to get SI value from measure unit (e.g. 1mi is equal to SI 1m
   multiplied by 1609.344)

3. Factor to get measure value from from SI value (e.g. SI 100m is equal to
   100mi divided by 1609.344)

The returned list is sorted, the first items are created from
``WIKIDATA_UNITS``, the second group of items is build from
:py:obj:`ADDITIONAL_UNITS` and items created from :py:obj:`ALIAS_SYMBOLS`.

If you search this list for a symbol, then a match with a symbol from
Wikidata has the highest weighting (first hit in the list), followed by the
symbols from the :py:obj:`ADDITIONAL_UNITS` and the lowest weighting is
given to the symbols resulting from the aliases :py:obj:`ALIAS_SYMBOLS`.

Definition at line 166 of file wikidata_units.py.

def symbol_to_si():
    """Generates a list of tuples, each tuple is a measure unit and the fields
    in the tuple are:
 
    0. Symbol of the measure unit (e.g. 'mi' for measure unit 'miles' Q253276)
 
    1. SI name of the measure unit (e.g. Q11573 for SI unit 'metre')
 
    2. Factor to get SI value from measure unit (e.g. 1mi is equal to SI 1m
       multiplied by 1609.344)
 
    3. Factor to get measure value from from SI value (e.g. SI 100m is equal to
       100mi divided by 1609.344)
 
    The returned list is sorted, the first items are created from
    ``WIKIDATA_UNITS``, the second group of items is build from
    :py:obj:`ADDITIONAL_UNITS` and items created from :py:obj:`ALIAS_SYMBOLS`.
 
    If you search this list for a symbol, then a match with a symbol from
    Wikidata has the highest weighting (first hit in the list), followed by the
    symbols from the :py:obj:`ADDITIONAL_UNITS` and the lowest weighting is
    given to the symbols resulting from the aliases :py:obj:`ALIAS_SYMBOLS`.
 
    """
 
    global SYMBOL_TO_SI  # pylint: disable=global-statement
    if SYMBOL_TO_SI:
        return SYMBOL_TO_SI
 
    # filter out units which can't be normalized to a SI unit and filter out
    # units without a symbol / arcsecond does not have a symbol
    # https://www.wikidata.org/wiki/Q829073
 
    for item in data.WIKIDATA_UNITS.values():
        if item['to_si_factor'] and item['symbol']:
            SYMBOL_TO_SI.append(
                (
                    item['symbol'],
                    item['si_name'],
                    1 / item['to_si_factor'],  # from_si
                    item['to_si_factor'],  # to_si
                    item['symbol'],
                )
            )
 
    for item in ADDITIONAL_UNITS:
        SYMBOL_TO_SI.append(
            (
                item['symbol'],
                item['si_name'],
                item['from_si'],
                item['to_si'],
                item['symbol'],
            )
        )
 
    alias_items = []
    for item in SYMBOL_TO_SI:
        for alias in ALIAS_SYMBOLS.get(item[0], ()):
            alias_items.append(
                (
                    alias,
                    item[1],
                    item[2],  # from_si
                    item[3],  # to_si
                    item[0],  # origin unit
                )
            )
    SYMBOL_TO_SI = SYMBOL_TO_SI + alias_items
    return SYMBOL_TO_SI
 
 
# the response contains duplicate ?item with the different ?symbol
# "ORDER BY ?item DESC(?rank) ?symbol" provides a deterministic result
# even if a ?item has different ?symbol of the same rank.
# A deterministic result
# see:
# * https://www.wikidata.org/wiki/Help:Ranking
# * https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Format ("Statement representation" section)
# * https://w.wiki/32BT
# * https://en.wikibooks.org/wiki/SPARQL/WIKIDATA_Precision,_Units_and_Coordinates#Quantities
#   see the result for https://www.wikidata.org/wiki/Q11582
#   there are multiple symbols the same rank
 

Referenced by units_by_si_name().

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units_by_si_name()

searx.wikidata_units.units_by_si_name

(

si_name

)

Definition at line 138 of file wikidata_units.py.

def units_by_si_name(si_name):
 
    global UNITS_BY_SI_NAME  # pylint: disable=global-statement,global-variable-not-assigned
    if UNITS_BY_SI_NAME:
        return UNITS_BY_SI_NAME[si_name]
 
    # build the catalog ..
    for item in symbol_to_si():
 
        item_si_name = item[pos_si_name]
        item_symbol = item[pos_symbol]
 
        by_symbol = UNITS_BY_SI_NAME.get(item_si_name)
        if by_symbol is None:
            by_symbol = {}
            UNITS_BY_SI_NAME[item_si_name] = by_symbol
        by_symbol[item_symbol] = item
 
    return UNITS_BY_SI_NAME[si_name]
 
 

References symbol_to_si().

Referenced by convert_from_si(), and convert_to_si().

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Variable Documentation

__all__

list searx.wikidata_units.__all__ = ["convert_from_si", "convert_to_si", "symbol_to_si"]

private

Definition at line 10 of file wikidata_units.py.

ADDITIONAL_UNITS

list searx.wikidata_units.ADDITIONAL_UNITS

Initial value:

=  [
    {
        "si_name": "Q11579",
        "symbol": "°C",
        "to_si": lambda val: val + 273.15,
        "from_si": lambda val: val - 273.15,
    },
    {
        "si_name": "Q11579",
        "symbol": "°F",
        "to_si": lambda val: (val + 459.67) * 5 / 9,
        "from_si": lambda val: (val * 9 / 5) - 459.67,
    },
    {
        "si_name": "Q182429",
        "symbol": "Bft",
        "to_si": Beaufort.to_si,
        "from_si": Beaufort.from_si,
    },
]

Definition at line 58 of file wikidata_units.py.

ALIAS_SYMBOLS

dict searx.wikidata_units.ALIAS_SYMBOLS

Initial value:

=  {
    '°C': ('C',),
    '°F': ('F',),
    'mi': ('L',),
    'Bft': ('bft',),
}

Definition at line 102 of file wikidata_units.py.

pos_from_si

int searx.wikidata_units.pos_from_si = 2

Definition at line 161 of file wikidata_units.py.

pos_si_name

int searx.wikidata_units.pos_si_name = 1

Definition at line 160 of file wikidata_units.py.

pos_symbol

int searx.wikidata_units.pos_symbol = 0

Definition at line 159 of file wikidata_units.py.

pos_to_si

int searx.wikidata_units.pos_to_si = 3

Definition at line 162 of file wikidata_units.py.

SARQL_REQUEST

str searx.wikidata_units.SARQL_REQUEST

Initial value:

=  """
SELECT DISTINCT ?item ?symbol ?tosi ?tosiUnit
WHERE
{
  ?item wdt:P31/wdt:P279 wd:Q47574 .
  ?item p:P5061 ?symbolP .
  ?symbolP ps:P5061 ?symbol ;
           wikibase:rank ?rank .
  OPTIONAL {
    ?item p:P2370 ?tosistmt .
    ?tosistmt psv:P2370 ?tosinode .
    ?tosinode wikibase:quantityAmount ?tosi .
    ?tosinode wikibase:quantityUnit ?tosiUnit .
  }
  FILTER(LANG(?symbol) = "en").
}
ORDER BY ?item DESC(?rank) ?symbol
"""

Definition at line 250 of file wikidata_units.py.

SYMBOL_TO_SI

list searx.wikidata_units.SYMBOL_TO_SI = []

Definition at line 116 of file wikidata_units.py.

UNITS_BY_SI_NAME

dict searx.wikidata_units.UNITS_BY_SI_NAME = {}

Definition at line 117 of file wikidata_units.py.