Thanks for your responses, Ken and Sarah.
I think you're date-routine function is going to come in handy and
dandy today, Ken. Thank you.
Sarah, in response to your question, I'm using version 2.6.1, build
152 for OS X. I used your handler below, but it returns the last
item of the dateItems, which is the numeric day of the week. Perhaps
I've misunderstood its purpose because my problem is with the way the
Convert command attempts to adjust hours. As my example shows and
Ken points out, Convert adds one hour during Daylight Savings Time
every time it is used on the same time-stamp. It should not. And
the bigger problem, thinking back on my research (gulp), is that it
does it with other date and time formats, not just the dateItems!
I'm going to be busy.
If I'm not mistaken, Convert is intended to convert date and time
formats for appearance, while the dateItems is intended to provide an
easy way to do date and time calculations, presumably when it is
included in home made functions. The Convert command should not make
any adjustment to dates or times because it cannot know whether it is
being fed actual values or being asked to make an adjustment for time
zones relative to GMT or for Daylight Savings Time. If an
observation I'm working with is June 2, 1963 3:00 PM, then that's
what it is. I may be working on a machine localized to Montreal or
Toronto, but that observation could refer to an event that took place
in Frankfurt. The Convert command simply does not have the
information it needs to make any adjustment and so should not. I
think the only way to do date and time calculations in Revolution is
to create functions specifically for that purpose. Finding what the
local date and time was five months, two days, and six hours ago, for
example, requires an adjustment for Daylight Savings Time; but the
number of hours that have passed since noon on August 28th, 2005 does
not. Programs like Mathematica make use of a function called
AbsoluteTime[] and AbsoluteTime[time zone], which is essentially the
Seconds in Revolution, but leaves all adjustments for Daylight
Savings Time up to the programmer because it is so idiosyncratic.
Mathematica's other date and time functions assume that all inputs
are local or from the same time zone. Taking a quick look at Excel
and FileMaker, I could not find any mention of built-in adjustments.
My recommendation is that Convert be made to simply convert formats.
Regards,
Gregory
_______________________________________________
use-revolution mailing list
[email protected]
Please visit this url to subscribe, unsubscribe and manage your subscription
preferences:
http://lists.runrev.com/mailman/listinfo/use-revolution
