Using DateDataParser¶
dateparser.parse()
uses a default parser which tries to detect language
every time it is called and is not the most efficient way while parsing dates
from the same source.
DateDataParser
provides an alternate and efficient way
to control language detection behavior.
The instance of DateDataParser
reduces the number
of applicable languages, until only one or no language is left. It
assumes the previously detected language for all the subsequent dates supplied.
This class wraps around the core dateparser
functionality, and by default
assumes that all of the dates fed to it are in the same language.
-
class
dateparser.date.
DateDataParser
(*args, **kwargs)[source]¶ Class which handles language detection, translation and subsequent generic parsing of string representing date and/or time.
Parameters: - languages (list) – A list of two letters language codes, e.g. [‘en’, ‘es’]. If languages are given, it will not attempt to detect the language.
- allow_redetect_language (bool) – Enables/disables language re-detection.
- settings (dict) – Configure customized behavior using settings defined in
dateparser.conf.Settings
.
Returns: A parser instance
Raises: ValueError - Unknown Language, TypeError - Languages argument must be a list
-
get_date_data
(date_string, date_formats=None)[source]¶ Parse string representing date and/or time in recognizable localized formats. Supports parsing multiple languages and timezones.
Parameters: Returns: a dict mapping keys to
datetime.datetime
object and period. For example: {‘date_obj’: datetime.datetime(2015, 6, 1, 0, 0), ‘period’: u’day’}Raises: ValueError - Unknown Language
Note
Period values can be a ‘day’ (default), ‘week’, ‘month’, ‘year’.
Period represents the granularity of date parsed from the given string.
In the example below, since no day information is present, the day is assumed to be current day
16
from current date (which is June 16, 2015, at the moment of writing this). Hence, the level of precision ismonth
:>>> DateDataParser().get_date_data(u'March 2015') {'date_obj': datetime.datetime(2015, 3, 16, 0, 0), 'period': u'month'}
Similarly, for date strings with no day and month information present, level of precision is
year
and day16
and month6
are from current_date.>>> DateDataParser().get_date_data(u'2014') {'date_obj': datetime.datetime(2014, 6, 16, 0, 0), 'period': u'year'}
Dates with time zone indications or UTC offsets are returned in UTC time unless specified using Settings.
>>> DateDataParser().get_date_data(u'23 March 2000, 1:21 PM CET') {'date_obj': datetime.datetime(2000, 3, 23, 14, 21), 'period': 'day'}
Warning
It fails to parse English dates in the example below, because Spanish was detected and stored with the ddp
instance:
>>> ddp.get_date_data('11 August 2012')
{'date_obj': None, 'period': 'day'}
dateparser.date.DateDataParser
can also be initialized with known languages:
>>> ddp = DateDataParser(languages=['de', 'nl'])
>>> ddp.get_date_data(u'vr jan 24, 2014 12:49')
{'date_obj': datetime.datetime(2014, 1, 24, 12, 49), 'period': u'day'}
>>> ddp.get_date_data(u'18.10.14 um 22:56 Uhr')
{'date_obj': datetime.datetime(2014, 10, 18, 22, 56), 'period': u'day'}
Settings¶
dateparser
‘s parsing behavior can be configured by supplying settings as a dictionary to settings argument in dateparser.parse or DateDataParser
constructor.
All supported settings with their usage examples are given below:
Date Order¶
DATE_ORDER
specifies the order in which date components year, month and day are expected while parsing ambiguous dates. It defaults to MDY which translates to month first, day second and year last order. Characters M, D or Y can be shuffled to meet required order. For example, DMY specifies day first, month second and year last order:
>>> parse('15-12-18 06:00') # assumes default order: MDY
datetime.datetime(2018, 12, 15, 6, 0) # since 15 is not a valid value for Month, it is swapped with Day's
>>> parse('15-12-18 06:00', settings={'DATE_ORDER': 'YMD'})
datetime.datetime(2015, 12, 18, 6, 0)
PREFER_LANGUAGE_DATE_ORDER
defaults to True. Most languages have a default DATE_ORDER specified for them. For example, for French it is DMY:
>>> # parsing ambiguous date
>>> parse('02-03-2016') # assumes english language, uses MDY date order
datetime.datetime(2016, 3, 2, 0, 0)
>>> parse('le 02-03-2016') # detects french, hence, uses DMY date order
datetime.datetime(2016, 3, 2, 0, 0)
Note
There’s no language level default DATE_ORDER associated with en language. That’s why it assumes MDY which is :obj:settings <dateparser.conf.settings>
default. If the language has a default DATE_ORDER associated, supplying custom date order will not be applied unless we set PREFER_LANGUAGE_DATE_ORDER to False:
>>> parse('le 02-03-2016', settings={'DATE_ORDER': 'MDY'})
datetime.datetime(2016, 3, 2, 0, 0) # MDY didn't apply
>>> parse('le 02-03-2016', settings={'DATE_ORDER': 'MDY', 'PREFER_LANGUAGE_DATE_ORDER': False})
datetime.datetime(2016, 2, 3, 0, 0) # MDY worked!
Handling Incomplete Dates¶
PREFER_DAY_OF_MONTH
This option comes handy when the date string is missing the day part. It defaults to current
and can have first
and last
denoting first and last day of months respectively as values:
>>> from dateparser import parse
>>> parse(u'December 2015') # default behavior
datetime.datetime(2015, 12, 16, 0, 0)
>>> parse(u'December 2015', settings={'PREFER_DAY_OF_MONTH': 'last'})
datetime.datetime(2015, 12, 31, 0, 0)
>>> parse(u'December 2015', settings={'PREFER_DAY_OF_MONTH': 'first'})
datetime.datetime(2015, 12, 1, 0, 0)
PREFER_DATES_FROM
defaults to current_period and can have past and future as values.
If date string is missing some part, this option ensures consistent results depending on the past or future preference, for example, assuming current date is June 16, 2015:
>>> from dateparser import parse
>>> parse(u'March')
datetime.datetime(2015, 3, 16, 0, 0)
>>> parse(u'March', settings={'PREFER_DATES_FROM': 'future'})
datetime.datetime(2016, 3, 16, 0, 0)
>>> # parsing with preference set for 'past'
>>> parse('August', settings={'PREFER_DATES_FROM': 'past'})
datetime.datetime(2015, 8, 15, 0, 0)
RELATIVE_BASE
allows setting the base datetime to use for interpreting partial or relative date strings.
Defaults to the current date and time.
For example, assuming current date is June 16, 2015:
>>> from dateparser import parse
>>> parse(u'14:30')
datetime.datetime(2015, 3, 16, 14, 30)
>>> parse(u'14:30', settings={'RELATIVE_BASE': datetime.datetime(2020, 1, 1)})
datetime.datetime(2020, 1, 1, 14, 30)
>>> parse(u'tomorrow', settings={'RELATIVE_BASE': datetime.datetime(2020, 1, 1)})
datetime.datetime(2020, 1, 2, 0, 0)
STRICT_PARSING
defaults to False.
When set to True if missing any of day, month or year parts, it does not return any result altogether.:
>>> parse(u'March', settings={'STRICT_PARSING': True})
None
Language Detection¶
SKIP_TOKENS
is a list
of tokens to discard while detecting language. Defaults to ['t']
which skips T in iso format datetime string .e.g. 2015-05-02T10:20:19+0000
.:
>>> from dateparser.date import DateDataParser
>>> DateDataParser(settings={'SKIP_TOKENS': ['de']}).get_date_data(u'27 Haziran 1981 de') # Turkish (at 27 June 1981)
{'date_obj': datetime.datetime(1981, 6, 27, 0, 0), 'period': 'day'}