> The real appeal for fixed records, when there are a > lot of them, is that they can be in a file that is > memory mapped to a rectangular array and then dealt > with in ways comfortable and efficient in J.
Not just J but any system of computation, and not just fixed length records but a representation that is as direct for the machine as possible (e.g. 4- or 8-byte integers; 8-byte floats). Nick Kostirya said there are 10 billion records, each consisting of (i,j,value) . ----- Original Message ----- From: Joey K Tuttle <[EMAIL PROTECTED]> Date: Saturday, January 5, 2008 20:26 Subject: RE: [Jgeneral] Successful stories To: General forum <[email protected]> > CSV Comma Separated Values. A popular export/import > option for databases and spreadsheets. Wikipedia is > a good source if you want/need more detail. There > are conversion routines (csv.ijs) distributed with J. > > CSV avoids fixed length rows, but as such are a "ragged > array" that isn't "first class" in J. A list of boxes > is similar in spirit to CSV and there are routines in > csv.ijs to switch between the two forms. > > The real appeal for fixed records, when there are a > lot of them, is that they can be in a file that is > memory mapped to a rectangular array and then dealt > with in ways comfortable and efficient in J. > > - joey > > > At 19:54 -0800 2008/01/05, Lynn & Bob Graf wrote: > >I'm a newbie at this. Don't exactly understand what a CSV > is, but > >perhaps the first time an abbreviation is used, could it be > written > >out, with the abbreviation in parens. This is the way > many > >technical reports are written - a nice courtesy. > > > >At any rate, on the subject, in addition to a matrix of fixed > length > >rows, what's wrong with a list of boxes? > > > >Bob in Boynton Beach, FL. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
