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Converting Epoch Seconds to DMYHMS

Problem

You have a date and time in Epoch seconds, and you want to calculate individual DMYHMS values from it.

Solution

In recipe TimeToday we did exactly this but only for the current date. How about if we wanted to get the date, and time (DMYHMS) associated to a particular number of seconds? Once more we would use seconds->date.

(require (lib "date.ss"))

(let* ((seconds 1083022458)
       (date (seconds->date seconds)))
  (date->string date))

that returns "Monday, April 26th, 2004".

Discussion

In recipe TimeToday we discussed how to convert a date structure to a string. Convert in th opposite direction is also possible, and useful. Here we use SRFI 19:

(require (lib "19.ss" "srfi"))

(let ((some-date-string "2004-04-26T18:26:18-0500"))
  (let ((date (string->date some-date-string "~Y-~m-~dT~k:~M:~S~z")))
    (values (date->string date)
            (date->string date "~4"))))

the resulting values will be: "Mon Apr 26 18:26:18-0500 2004", and "2004-04-26T18:26:18-0500", which represent the same date, and time but using two different formats described in ISO-8601.

Important: Note that the second argument to string->date is a formatting string that must match the format of the actual date-hour string used as the first argument.

Comments here

-- FranciscoSolsona - 28 Apr 2004