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Date_Time_Formatter.from_simple_pattern

Date_Time_Formatter.from_simple_patternpatternlocale

Documentation​

Creates a formatter from a simple date-time format pattern. Every letter in the pattern is interpreted as a pattern character as described in the table below. Any character that is not a letter in the pattern is treated as a literal character. If a sequence of letters needs to be put in as a literal, it can be escaped using single quotes. Use two single quotes in a row to represent a single quote in the result. As explained below, curly braces can have special meaning (see 'yy'); to enter a literal curly brace, put it inside a quoted literal. Pattern characters are interpreted case insensitively, with the exception of `M/m' and 'H/h'.

Examples​

Parsing date/time values​

      Date_Time.parse "2021-10-12T12:34:56.789+0200" "yyyy-MM-dd'T'HH:mm:ss.fZ" == (Date_Time.new 2021 10 12 12 34 56 millisecond=789 zone=(Time_Zone.new hours=2))
      Date.parse "Tue, 12 Oct 2021" "ddd, d MMM yyyy" == (Date.new 2021 10 12)
      Date_Time.parse "12/10/2021 5:34 PM" "d/M/Y h:mm a" == (Date_Time.new 2021 10 12 17 34 00)

Note that the default locale may not support full-length day/month names, so you may need to set a specific locale for this to work.​

      Date.parse "Thursday, 1 October '98" (Date_Time_Formatter.from "dddd, d MMMM ''yy" Locale.uk) == (Date.new 1998 10 01)

Omitting the day will yield the first day of the month.​

      Date.parse "2021-10" "yyyy-MM" == (Date.new 2021 10 01)

Omitting the year will yield the current year.​

      Date.parse "10-12" "MM-dd" == (Date.new (Date.today.year) 10 12)

Parsing a two-digit year with a custom base year.​

      Date.parse "1 Nov '95" "d MMM ''yy{2099}" == (Date.new 2095 11 01)

Remarks​

Date pattern characters​

  • y: Year. The number of pattern letters determines the minimum number of digits.
    • y: The year using any number of digits.
    • yy: The year, using at most two digits. The default range is 1950-2049, but this can be changed by including the end year in braces e.g. yy{2099}.
    • yyyy: The year, using exactly four digits.
  • M: Month of year. The number of pattern letters determines the format:
    • M: Any number (1-12).
    • MM: Month number with zero padding required (01-12).
    • MMM: Short name of the month (Jan-Dec).
    • MMMM: Full name of the month (January-December). The month names depend on the selected locale.
  • d: Day. The number of pattern letters determines the format:
    • d: Any number (1-31).
    • dd: Day number with zero padding required (01-31).
    • ddd: Short name of the day of week (Mon-Sun).
    • dddd: Full name of the day of week (Monday-Sunday). The weekday names depend on the selected locale. Both day of week and day of month may be included in a single pattern - in such case the day of week is used as a sanity check.
  • e: An alternative notation: single e maps to ddd and ee or more map to dddd meaning name of day of week.
  • Q: Quarter of year. If only year and quarter are provided in the pattern, when parsing a date, the result will be the first day of that quarter.

Time pattern characters​

  • H: 24h hour of day (0-23).
  • h: 12h hour of day (0-12). The a pattern is needed to disambiguate between AM and PM.
  • m: Minute of hour.
  • s: Second of minute.
  • f: Fractional part of the second. The number of pattern letters determines the number of digits. If one letter is used, any number of digits will be accepted.
  • a: AM/PM marker.

Time zone pattern characters​

  • T: If repeated 3 or less times - Time zone ID (e.g. Europe/Warsaw, Z, -08:30), otherwise - Time zone name (e.g. Central European Time, CET).
  • Z: Zone offset.
    • Z, ZZ, ZZZ: A short offset form (+HHmm). No offset is indicated by "+0000". This can be customized by setting an alternative no offset string in curly braces, e.g. zz{Z}.
    • ZZZZ: Localized offset (e.g. GMT-08:00).
    • ZZZZZ: A full offset form (+HH:mm:ss). No offset is indicated by "Z". This can be customized as above, e.g. ZZZZZ{0}.
  • v: Time zone name (same as TTTT).
  • V: Time zone ID (same as T).

Some parts, like fractions of a second may not be required. The square brackets [] can be used to surround such optional sections.