date-time-year

Arguments: date-time

Returns the year (an integer) of the date represented in date-time if that value can be calculated by non-nil slots in date-time, and returns nil otherwise. date-time must be a date-time object.

There is no year slot in a date-time instance. This function calculates its value from other slots (such as ymd-yd-century and ymd-yd-year-in-century). If nil is returned, it may be because the date-time is not complete (so needed slots are not filled in) or because the date portion is incomplete (needed information is not available, such as when a relative date -- "85-10-10" -- is all that is provided.) In the first case, applying complete-date-time will fill in needed slots. In the second case, it will not.

(require :datetime)
(use-package :util.date-time)

;; date-time is 1985/04/12 10:15:30, that is 15 and a half
;; minutes after 10 AM April 12, 1985.
(setq a (date-time "1985-04-12T10:15:30"))
(date-time-year a) -> 1985

See date-time.htm for information on support in Allegro CL for parsing and generating time expressions using the ISO 8601 standard.

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This page was not revised from the 10.0 page.
Created 2019.8.20.