parsing time stamp

parsing time stamp

[Xah]

is there a function that parses a timestamp like “Monday, Nov. 28,
1994” so that i can write a function to turn it into the format yyyy-
mm-dd?

Thanks in advance.

  Xah
  xah@xahlee.org
∑ http://xahlee.org/

☄

RE: parsing time stamp

[Drew Adams]

> is there a function that parses a timestamp like "Monday, Nov. 28,
> 1994" so that i can write a function to turn it into the format yyyy-
> mm-dd?

It would be useful, but I don't think so. 

See thread "regexp to match formatted time string?" in emacs-devel@gnu.org,
2008-02-01:
http://lists.gnu.org/archive/html/emacs-devel/2008-02/msg00060.html

Re: parsing time stamp

[David Hansen]

On Thu, 22 May 2008 11:25:08 -0700 (PDT) Xah wrote:

> is there a function that parses a timestamp like “Monday, Nov. 28,
> 1994” so that i can write a function to turn it into the format yyyy-
> mm-dd?

I'm pretty sure there is such a function in Gnus and Emacs-w3m.

David

Re: parsing time stamp

[Johan Bockgård]

Xah <xahlee@gmail.com> writes:

> is there a function that parses a timestamp like “Monday, Nov. 28,
> 1994” so that i can write a function to turn it into the format yyyy-
> mm-dd?

parse-time-string

-- 
Johan Bockgård

Re: parsing time stamp

[Kevin Rodgers]

Johan Bockgård wrote:
> Xah <xahlee@gmail.com> writes:
> 
>> is there a function that parses a timestamp like “Monday, Nov. 28,
>> 1994” so that i can write a function to turn it into the format yyyy-
>> mm-dd?
> 
> parse-time-string

(parse-time-string "Monday, Nov. 28, 1994")
=> (nil nil nil 28 11 1994 nil nil nil)

Odd that the leading "Monday, " yields nil DOW...  It turns out that is
due to the fact that the parse-time-weekdays variable only has
abbreviations (e.g. "mon"), just like parse-time-months.  Easy to fix:

(let ((parse-time-weekdays (append parse-time-weekdays
				   '(("sunday" . 0)
				     ("monday" . 1)
				     ("tuesday" . 2)
				     ("wednesday" . 3)
				     ("thursday" . 4)
				     ("friday" . 5)
				     ("saturday" . 6)))))
   (parse-time-string "Monday, Nov. 28, 1994"))
=> (nil nil nil 28 11 1994 1 nil nil)

-- 
Kevin Rodgers
Denver, Colorado, USA

Re: parsing time stamp

[Kevin Rodgers]

Kevin Rodgers wrote:
> Johan Bockgård wrote:
>> Xah <xahlee@gmail.com> writes:
>>
>>> is there a function that parses a timestamp like “Monday, Nov. 28,
>>> 1994” so that i can write a function to turn it into the format yyyy-
>>> mm-dd?
>>
>> parse-time-string
> 
> (parse-time-string "Monday, Nov. 28, 1994")
> => (nil nil nil 28 11 1994 nil nil nil)
> 
> Odd that the leading "Monday, " yields nil DOW...  It turns out that is
> due to the fact that the parse-time-weekdays variable only has
> abbreviations (e.g. "mon"), just like parse-time-months.  Easy to fix:
> 
> (let ((parse-time-weekdays (append parse-time-weekdays
>                    '(("sunday" . 0)
>                      ("monday" . 1)
>                      ("tuesday" . 2)
>                      ("wednesday" . 3)
>                      ("thursday" . 4)
>                      ("friday" . 5)
>                      ("saturday" . 6)))))
>   (parse-time-string "Monday, Nov. 28, 1994"))
> => (nil nil nil 28 11 1994 1 nil nil)

That reminds me of a hack I put together a few years ago, to generate a
list of both day names and abbreviations, which are sensitive to the
locale:

   (let ((year (string-to-number (format-time-string "%Y")))
         (month (string-to-number (format-time-string "%m"))))
     (apply 'nconc
            (mapcar (lambda (time)
                      (list (format-time-string "%a." time)
                            (format-time-string "%A" time)))
                    (sort (mapcar (lambda (day)
                                    (encode-time 0 0 0 day month year 0))
                                  '(1 2 3 4 5 6 7))
                          ;; by day of week:
                          (lambda (time-1 time-2)
                            (< (nth 6 (decode-time time-1))
                               (nth 6 (decode-time time-2))))))))

Perhaps that could be incorporated into the initial value of
parse-time-weekdays to handle localized time strings.  There's also a
corresponding hack for month names and abbreviations (parse-time-months):

   (let ((year (string-to-number (format-time-string "%Y"))))
     (apply 'nconc
            (mapcar (lambda (month)
                      (let ((first (encode-time 0 0 0 1 month year 0)))
                        (list (format-time-string "%b." first t)
                              (format-time-string "%B" first t))))
                    '(1 2 3 4 5 6 7 8 9 10 11 12))))

-- 
Kevin Rodgers
Denver, Colorado, USA