Pyparsing — удобный модуль Python для разбора таких строк. Вот аннотированный синтаксический анализатор, который взламывает ваши входные строки и дает месяцы, дни и годы для каждой:
import pyparsing as pp
import calendar
COMMA = pp.Suppress(',')
AMP = pp.Suppress('&')
DASH = pp.Suppress('-')
# use pyparsing-defined integer expression, which auto-converts parsed str's to int's
day_number = pp.pyparsing_common.integer()
# day numbers only go from 1-31
day_number.addCondition(lambda t: 1 <= t[0] <= 31)
# not in the spec, but let's support day ranges, too!
day_range = day_number("first") + DASH + day_number("last")
# parse-time conversion from "4-6" to [4, 5, 6]
day_range.addParseAction(lambda t: list(range(t.first, t.last+1)))
# this function will come in handy to build list parsers of day numbers and month-day
expr_list = lambda expr: expr + pp.ZeroOrMore(COMMA + expr) + pp.Optional(AMP + expr)
# support "10", "10 & 11", "10, 11, & 12"
day_list = expr_list(day_range | day_number)
# get the month names from the calendar module
month_name = pp.oneOf(calendar.month_name[1:])
# an expression containing a month name and a list of 1 or more day numbers
date_expr = pp.Group(month_name("month") + day_list("days"))
# use expr_list again to support multiple date_exprs separated by commas and ampersands
date_list = expr_list(date_expr)
year_number = pp.pyparsing_common.integer()
# year numbers start with 2000
year_number.addCondition(lambda t: t[0] >= 2000)
# put all together into a single parser expression
full_date = date_list("dates") + COMMA + year_number("year")
tests = """\
March 20 & June 8, 2011
September 4 & 27, 2010
February 15, December 5 & 6, 2013
September 4-6, 2010
"""
full_date.runTests(tests)
Отпечатки:
March 20 & June 8, 2011
[['March', 20], ['June', 8], 2011]
- dates: [['March', 20], ['June', 8]]
[0]:
['March', 20]
- days: [20]
- month: 'March'
[1]:
['June', 8]
- days: [8]
- month: 'June'
- year: 2011
September 4 & 27, 2010
[['September', 4, 27], 2010]
- dates: [['September', 4, 27]]
[0]:
['September', 4, 27]
- days: [4, 27]
- month: 'September'
- year: 2010
February 15, December 5 & 6, 2013
[['February', 15], ['December', 5, 6], 2013]
- dates: [['February', 15], ['December', 5, 6]]
[0]:
['February', 15]
- days: [15]
- month: 'February'
[1]:
['December', 5, 6]
- days: [5, 6]
- month: 'December'
- year: 2013
September 4-6, 2010
[['September', 4, 5, 6], 2010]
- dates: [['September', 4, 5, 6]]
[0]:
['September', 4, 5, 6]
- days: [4, 5, 6]
- month: 'September'
- year: 2010
Чтобы получить кортежи (год, месяц, день), мы добавляем еще одно действие синтаксического анализа и перезапускаем тесты:
print("convert parsed fields into (year, month-name, date) tuples")
def expand_dates(t):
return [(t.year, d.month, dy) for d in t.dates for dy in d.days]
full_date.addParseAction(expand_dates)
full_date.runTests(tests)
Отпечатки:
convert parsed fields into (year, month-name, date) tuples
March 20 & June 8, 2011
[(2011, 'March', 20), (2011, 'June', 8)]
September 4 & 27, 2010
[(2010, 'September', 4), (2010, 'September', 27)]
February 15, December 5 & 6, 2013
[(2013, 'February', 15), (2013, 'December', 5), (2013, 'December', 6)]
September 4-6, 2010
[(2010, 'September', 4), (2010, 'September', 5), (2010, 'September', 6)]
Наконец, превратите их в объекты datetime.date
с помощью другого действия синтаксического анализа:
print("convert (year, month-name, date) tuples into datetime.date's")
# define mapping of month-name to month number 1-12
month_map = {name: num for num,name in enumerate(calendar.month_name[1:], start=1)}
from datetime import date
full_date.addParseAction(pp.tokenMap(lambda t: date(t[0], month_map[t[1]], t[2])))
full_date.runTests(tests)
Отпечатки:
convert (year, month-name, date) tuples into datetime.date's
March 20 & June 8, 2011
[datetime.date(2011, 3, 20), datetime.date(2011, 6, 8)]
September 4 & 27, 2010
[datetime.date(2010, 9, 4), datetime.date(2010, 9, 27)]
February 15, December 5 & 6, 2013
[datetime.date(2013, 2, 15), datetime.date(2013, 12, 5), datetime.date(2013, 12, 6)]
September 4-6, 2010
[datetime.date(2010, 9, 4), datetime.date(2010, 9, 5), datetime.date(2010, 9, 6)]
person
PaulMcG
schedule
22.08.2018
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и,
, чтобы сначала выполнить начальный анализ? - person user12205   schedule 21.08.2018