Creating Date and Time Stamps

How about two lines that can be pasted in where needed:
wDate = Year(Now) & Right("00" & Month(Now), 2) & Right("00" & Day(Now), 2)
wTime = Right("00" & Hour(Now), 2) & Right("00" & Minute(Now), 2)

craigm3604 August 04, 2007 (Article Rating: )

Sorry - correction:
wDate = Year(Now) & Right("00" & Month(Now), 2) & Right("00" & Day(Now), 2)
wTime = Right("00" & Hour(Now), 2) & Right("00" & Minute(Now), 2) & Right("00" & Second(Now), 2)

craigm3604 August 04, 2007 (Article Rating: )

Craig,
using
Right("00" & <something>, 2)
is a very nice trick. I've adapted the two generic drop-in functions to use it, as shown below.

Function ToDateStamp(ByVal dt)
ToDateStamp = Year(dt) _
& Right("00" & Month(dt), 2) _
& Right("00" & Day(dt), 2)
End Function

Function ToTimeStamp(ByVal dt)
ToTimeStamp = Right("00" & Hour(dt), 2) _
& Right("00" & Minute(dt), 2) _
& Right("00" & Second(dt), 2)
End Function

Thanks for raising the point!

AlexKAngelopoulos August 10, 2007 (Article Rating: )

Without knowing it had a definition, I've been using ISO 8601 format for some time for just the advantages you listed, in particular that this format is easy to understand and read, and that it sorts very nicely.

From a CMD file, you can create an ISO 8601 compatible string for the date by using this:

FOR /F "tokens=2-4 delims=/ " %%f in ("%date%") do set ISO9601Date=%%h%%f%%g

Note that I'm using two delimiters here, a forward slash AND a space, the space is necessary to lop off the day of the week from the front of the date variable.

and for time, use

FOR /F "tokens=1-3 delims=:." %%f in ("%time: =0%") do set ISO9601Time=%%f%%g%%h


The %time: =0% (after the colon it is 'space equals 0' changes all the blanks in the time variable to 0, taking care of the single digit hour issue

(These were prepared on Windows XP Pro using English-US regional settings. Your configuration may require this code to be tweaked)

Jim

TheFormatter June 06, 2008 (Article Rating: )

what about an even easier approach?

wDate = CStr(Year(Now) * 10000 + Month(Now) * 100 + Day(Now))
wTime = Right(CStr(1000000 + Hour(Now) * 10000 + Minute(Now) * 100 + Second(Now)), 6)

to get an ISO date in a batch file just put the mathematical part of the aforementioned expressions (ie without the string functions) in a vbscript file and return the result with WScript.Quit, like

WScript.Quit(Year(Now) * 10000 + Month(dtNow) * 100 + Day(Now))

and retrieve the value by using %ErrorLevel%

OlliK June 06, 2008 (Article Rating: )

The standard gives several formats, and I find the format <YYYY><MM><DD>T<hh>:<mm>:<ss.ddd><timezoneletter> more readable. Unfortunately one has to define the format in the given language.
But it is defently worth the effort.

NielsGrove June 06, 2008 (Article Rating: )

Jim -
These look like they work on Vista with default US date/time settings as well. Unfortunately, I found the cmd approach doesn't work very well if the settings are already in an ISO8601 form (although it _should_ be possible to make a batch file that uses reg.exe to check the registry for the current date settings format and base parsing on that).

AlexKAngelopoulos June 11, 2008 (Article Rating: )

OlliK -
The approach you show is definitely more compact, but there actually is a case where it could be a problem due to the discrete amount of time it takes for each evaluation of Now().
If you're generating a date/time stamp right around the time when the year, month, day, hour, or minute is about to increment, you can get a bad value generated. It's going to be very rare of course, but it could be bizarre in the worst possible cases. As an example, suppose the code is running at approximately midnight on 2008 December 31. By evaluating Now() once, you get a specific value that may turn out to be
20081231 235959
or, if run milliseconds later,
20090101 000000
The first one is just before the beginning of the year, the second is just after the beginning of the year.
However, with multiple evaluations of Now(), wDate might be evaluated before midnight as 20081231 and wTime right after midnight, giving you
20081231 000000
which is 24 hours earlier! It could even happen within a line of code; VBScript evaluates right to left, so if the date changes immediately after the day is evaluated, then you would get
20091231 000000
which is almost a year off.
The code runs _very_ fast on modern machines so I would be very surprised to see this happen, but the mere possibility would qualify as a bug. That's why I use the longer way that evaluates Now() once.

AlexKAngelopoulos June 11, 2008 (Article Rating: )