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Re: Daylight savings time in DatePlus.

  • To: mathgroup at smc.vnet.net
  • Subject: [mg124534] Re: Daylight savings time in DatePlus.
  • From: W Craig Carter <ccarter at mit.edu>
  • Date: Mon, 23 Jan 2012 02:57:20 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201201200652.BAA18151@smc.vnet.net> <000001ccd7f1$932b2430$b9816c90$@net>

Thank you Hans,
Very nice.

However, it seems that this can't be generalized without direct input of 
the daylight savings time shifts for each region where the data is 
taken.

I suppose there may be case for curated data in this case. Although I 
don't imagine that it would have a large audience.  Astronomical data 
comes to mind as one possible place where curated data and methods would 
be useful---there is a current debate about adding a leap second.

In any case, many thanks for your time and effort, Craig


W Craig Carter
Professor of Materials Science, MIT



On Jan 20, 2012, at Fri, Jan 20, 12 ---11:03 PM, Hans Michel wrote:

> Craig:
>
> Working with just your example, using time zones
>
> Map[Function[
>  DateString[ #1, If[Last[#1] < 2, TimeZone -> -6, TimeZone -> -5]]],
> Map[Function[DatePlus[{2010, 1, 1, 1}, {#1, "Hour"}]],
>  Range[1728, 1738]]]
>
> {Sun 14 Mar 2010 01:00:00,Sun 14 Mar 2010 03:00:00,Sun 14 Mar 2010
> 04:00:00,Sun 14 Mar 2010 05:00:00,Sun 14 Mar 2010 06:00:00,Sun 14 Mar 2010
> 07:00:00,Sun 14 Mar 2010 08:00:00,Sun 14 Mar 2010 09:00:00,Sun 14 Mar 2010
> 10:00:00,Sun 14 Mar 2010 11:00:00,Sun 14 Mar 2010 12:00:00}
>
> Hans
>
> -----Original Message-----
> From: W Craig Carter [mailto:ccarter at mit.edu]
> Sent: Friday, January 20, 2012 12:52 AM
> To: mathgroup at smc.vnet.net
> Subject: Daylight savings time in DatePlus.
>
> Hello,
> I need to account for daylight savings time in list of data representing
> each hour in year 2010. I would like to correlate that with other data
> taken at 15 second intervals in the same year.
>
> In 2010 daylight savings time in the US began on 14 March 2AM.
>
> DateDifference[{2010, 1, 1, 1}, {2010, 3, 14, 1}, "Hour"] (*1728 hours after
> beginning of year*)
>
> DateString /@ (DatePlus[{2010, 1, 1, 1}, {#, "Hour"}] & /@Range[1728, 1738])
>
> (*doesn't reflect that 3AM should follow 1AM*)
>
>
> In hindsight, this is not surprising because daylight savings time
> shifts are not standardized intranationally or internationally.  I don't
> see any clever work-around. Does anyone else?
>
> Craig
>
>
>
> W Craig Carter
> Professor of Materials Science, MIT
>
>
>
>




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