Module: ParseDate::IntFromString

Included in:
ParseDate
Defined in:
lib/parse_date/int_from_string.rb

Overview

Parse (Year) Integers from Date Strings

Class Method Summary collapse

Class Method Details

.earliest_year(date_str) ⇒ Integer?

earliest year as Integer if we can parse one from date_str

e.g. if 17uu, result is 1700

NOTE: if we have a x/x/yy or x-x-yy pattern (the only 2 digit year patterns

found in our actual date strings in stanford-mods records), then
we use 20 as century digits unless it is greater than current year:
1/1/17  ->  2017
1/1/27  ->  1927

Returns:

  • (Integer, nil) —

    Integer year if we could parse one, nil otherwise



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# File 'lib/parse_date/int_from_string.rb', line 18

def self.earliest_year(date_str)
  return unless date_str && !date_str.empty?
  return if date_str == '0000-00-00' # shpc collection has these useless dates

  # B.C. first (match longest string first)
  return ParseDate.send(:earliest_century_bc, date_str) if date_str.match(YY_YY_CENTURY_BC_REGEX)
  return ParseDate.send(:between_bc_earliest_year, date_str) if date_str.match(BETWEEN_Yn_AND_Yn_BC_REGEX)
  return ParseDate.send(:year_int_for_bc, date_str) if date_str.match(YEAR_BC_REGEX)

  result ||= ParseDate.send(:between_earliest_year, date_str)
  result ||= ParseDate.send(:hyphen_4digit_earliest_year, date_str)
  result ||= ParseDate.send(:negative_first_four_digits, date_str)
  result ||= ParseDate.send(:first_four_digits, date_str)
  result ||= ParseDate.send(:year_from_mm_dd_yy, date_str)
  result ||= ParseDate.send(:first_year_for_decade, date_str) # 198x or 201x
  result ||= ParseDate.send(:first_year_for_century, date_str) # includes BC
  result ||= ParseDate.send(:year_for_early_numeric, date_str)
  unless result
    # try removing brackets between digits in case we have 169[5] or [18]91
    no_brackets = ParseDate.send(:remove_brackets, date_str)
    return earliest_year(no_brackets) if no_brackets
  end
  result.to_i if result && year_int_valid?(result.to_i)
end

.latest_year(date_str) ⇒ Integer?

latest year as Integer if we can parse one from date_str

e.g. if 17uu, result is 1799

NOTE: if we have a x/x/yy or x-x-yy pattern (the only 2 digit year patterns

found in our actual date strings in stanford-mods records), then
we use 20 as century digits unless it is greater than current year:
1/1/17  ->  2017
1/1/27  ->  1927

Returns:

  • (Integer, nil) —

    Integer year if we could parse one, nil otherwise



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# File 'lib/parse_date/int_from_string.rb', line 51

def self.latest_year(date_str)
  return unless date_str && !date_str.empty?
  return if date_str == '0000-00-00' # shpc collection has these useless dates

  # B.C. first (match longest string first)
  return ParseDate.send(:last_year_mult_centuries_bc, date_str) if date_str.match(YY_YY_CENTURY_BC_REGEX)
  return ParseDate.send(:between_bc_latest_year, date_str) if date_str.match(BETWEEN_Yn_AND_Yn_BC_REGEX)
  return ParseDate.send(:last_year_for_bc_century, date_str) if date_str.match(BC_CENTURY_REGEX)
  return ParseDate.send(:year_int_for_bc, date_str) if date_str.match(BC_REGEX)

  result ||= ParseDate.send(:between_latest_year, date_str)
  result ||= ParseDate.send(:hyphen_4digit_latest_year, date_str)
  result ||= ParseDate.send(:hyphen_2digit_latest_year, date_str)
  result ||= ParseDate.send(:yyuu_after_hyphen, date_str)
  result ||= ParseDate.send(:year_after_or, date_str)
  result ||= ParseDate.send(:negative_4digits_after_hyphen, date_str)
  result ||= ParseDate.send(:negative_first_four_digits, date_str)
  result ||= ParseDate.send(:last_year_for_0s_decade, date_str)
  result ||= ParseDate.send(:first_four_digits, date_str)
  result ||= ParseDate.send(:year_from_mm_dd_yy, date_str)
  result ||= ParseDate.send(:last_year_for_decade, date_str) # 198x or 201x
  result ||= ParseDate.send(:last_year_mult_centuries, date_str) # nth-nth century
  result ||= ParseDate.send(:last_year_for_century, date_str)
  result ||= ParseDate.send(:last_year_for_early_numeric, date_str)
  unless result
    # try removing brackets between digits in case we have 169[5] or [18]91
    no_brackets = ParseDate.send(:remove_brackets, date_str)
    return earliest_year(no_brackets) if no_brackets
  end
  result.to_i if result && year_int_valid?(result.to_i)
end

.year_int_valid?(year) ⇒ Boolean

true if the year is between -9999 and (current year + 1), inclusive

Returns:

  • (Boolean) —

    true if the year is between -999 and (current year + 1); false otherwise



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# File 'lib/parse_date/int_from_string.rb', line 85

def self.year_int_valid?(year)
  return false unless year.is_a? Integer

  (-10000 < year.to_i) && (year < Date.today.year + 2)
end