sorting by date senile?

[xbury.cs at clearstream.com]

Mark,

Thanks very much! I agree you rely on other subsystems to get your dates
sorted and surely an improvement seems desirable!

You're explanations are awesome and have clarified the obscure conversion
problem I was experienceing on top of this other problem! 

Thanks again for your help! Im glad the RevPeople are joining the 
discussion! ;)

regards,
Xavier

On 09.03.2005 17:53:09 use-revolution-bounces wrote:
>Hi Xavier,
>
>> Thanks but that is rather arcane! I thought this was a modern tool ;)
>
>Perhaps a little arcane - Revolution currently relies on the underlying
>OS for it's date conversion routines - which means time started at
>midnight on 01/01/1970 for the most part.
>
>> Would using internet time or the dateitems format work better?
>
>The internet date, while ideal for transmitting dates (as you can also
>encode the time-zone), is not really suitable for sorting as it is
>designed to be human readable, more than machine processable.
>
>dateItems can be used to sort, but you'd need to sort by each item in
>turn:
>put <list of dateItems> into tList
>repeat with n = 1 to 7
>sort lines of tList ascending numeric by item n of each
>end repeat
>
>(the stability of Transcript's sort means that this works fine)
>
>Of course by encoding your dates in the form:
>YYYY/MM/DD
>You can just use a string sort. Similarly:
>YYYY/MM/DD HH:MM:SS
>Can be sorted using a string sort too.
>
>(the separators used in these cases is irrelevant, as long as it is
>consistent)
>
>> repeat with x = 1 to the number of lines in histo
>>    convert (item 1 of line x of histo) to dateitems
>> Result = nothing! convert puts the conversion into it! ;((
>
>This is (relatively) consistent with other commands. The 'convert'
>command expects a container as its first argument - and if one is not
>supplied it will use the default container: it.
>
>In your above syntax you have forced Revolution to evaluate the
>container expression as a string by using parantheses. If you were to
>do:
>convert item 1 of line x of histo to dateItems
>It would do the conversion in place.
>
>> a little fix for this second weird thing!
>>
>> Date items now doesn't convert anything before the year 1970!
>>
>> Not in the docs either! Or did I miss that? Not in the limits either!
>> I added a webnote to the rev docs and I guess this means a dozen
>> new functions in XOS to handles these correctly!
>>
>> Since I suppose this wont work with the "seconds" for a "simple" 
numeric
>> sort, we now have to resort to 3 sorts, one for each date item!
>> Triple the inneficiency here! 6X if you use the time as a factor! ;)
>
>There is no trouble sorting the seconds numerically - but remember, the
>seconds counts the number of seconds since 1970 :o)
>
>> >You will have to do some math, but you are good at that ;-)
>>
>> Im good at math - but I hate to do it for a system / person
>> that is supposed to do it better and faster than me!
>>
>> I tried the usesystemdate but it didn't help.
>
>Setting the useSystemDate property causes the date and the time to
>format their result using the current system locale as opposed to US
>standard formats.
>
>> I dont dare use the centurycutoff as it makes things even more 
confusing!
>> Where does the century start and stop now?
>
>The centuryCutOff property is only relevant when considering dates with
>two digits and determines where the current century ends. If the two
>digit year <= centuryCutOff, then it is assumed that it maps to a year
>in the current century, else it assumes it maps to a year in the
>previous century.
>
>e.g. We are in 2005, setting centuryCutOff to 20 will result in:
>01/01/15 => 01/01/2015
>01/01/25 => 01/01/1925
>
>Hope this clarifies a few things,
>
>Warmest Regards,
>
>Mark.
>
>------------------------------------------------------------------
>Mark Waddingham ~ 36degrees at runrev.com ~ http://www.runrev.com
>Runtime Revolution ~ User-Centric Development Tools
>
>_______________________________________________
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>use-revolution at lists.runrev.com
>http://lists.runrev.com/mailman/listinfo/use-revolution


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