What about time zone? On Sat, Jan 3, 2009 at 11:44 PM, neville holmes <[email protected]>wrote:
> David Vincent-Jones wrote: > > > I have a series of time-stamps taken from a pump station where I need > to > > evaluate the operating intervals in minutes. > > > > . . . > > > > I have been doing this the hard way with lots of 'intervention' but > > probably somebody has already solved this elegantly and ideas would > be > > appreciated. > > > At the risk of boring (annoying?) those who have read my ideas > on this topic here before, I would like to point out briefly how J > could handle such matters very elegantly indeed. > > Times and dates are very commonly used in calculations and > are not able to be simplified in the way that weights and > measures and money have been persuaded to be wholly > decimal. > > Therefore it is feasible to express times and dates in much > the same way that 1j2 and 3r4 and the like are expressed. > A date would have at least a y and an m embedded as in > 2008y12m01 and this could be extended to greater precision > as in 2008y12m1d1h46m19 for example. > > The difference between two dates would be a time interval > expressible for example as 2h34m58.56 with the possibility > of including days and possibly weeks in front of such > values. > > There would need to be rules as to how the different > arithmetic functions would handle date or time arguments; > for example a time could be added to or subtracted from > a date but not multiplied; a time interval could be multiplied > or divided by an ordinary number, but not added or subtracted. > > There would need to be functions analogous to j. to construct > times or dates from ordinary numbers, others to extract > ordinary numbers from dates or times and to format them > for printing. > > This is only a brief description, and clearly it would take > a good deal of work to fully design and implement such > a facility. I would argue, however, that the simplicity of > representation and conversion of such important values > as dates and times, and the ability to put them into > numeric arrays without boxing, would make the effort > well worthwhile. It would also allow such matters > as leap years and leap seconds to be handled by the J > interpreter, a further simplification and one which would > remove the source of inaccuracies. > > Neville Holmes, P.O. Box 2412, Bakery Hill 3354, Victoria > > > Stay connected to the people that matter most with a smarter inbox. > Take a look http://au.docs.yahoo.com/mail/smarterinbox > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
