Hello Mikl; It seems that you're asserting that:
NEW -: foo OLD I would agree, and can see what foo would be, if NEW =: 0 1 2 3 7 8 10 11 12 13 17 18 but I don't see how you get the NEW you do get. Please tell me what my mistake is. ------------------------------------------------------------------------ |\/| Randy A MacDonald | APL: If you can say it, it's done.. (ram) |/\| [EMAIL PROTECTED] | |\ | |If you cannot describe what you are doing BSc(Math) UNBF'83 ?as a process, you don't know what you're doing. Sapere Aude | - W. E. Deming Natural Born APL'er | Demo website: http://156.34.69.76/ -----------------------------------------------------(INTP)----{ gnat }- ----- Original Message ----- From: "Mikl Kurkov" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, June 11, 2006 4:21 PM Subject: [Jprogramming] Index converter > I have task for which I couldn't find a solution. > > Suppose we have some indexes which relate to some data. > Now I have vector which describe which indexes to keep and which to remove. > > For example: pat =: 4 _3 2 _1 > > Positive value - tell how many indexes to keep, negative to remove. So the > pat is telling that I need to keep 4 first indexes then remove 3 next, > keep another 2, remove 1, keep 4, remove 3 and so on. > I need function that for giving index give me new index after applying > such pattern. Indexes of removed items - is index of next keeped item. > > So applying this function to i.20 and pat I should see: > OLD: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 > NEW: 0 1 2 3 4 4 4 4 5 6 6 7 8 9 10 10 10 10 11 12 > > Another function will make inverse calculation - for each value from NEW > give the biggest value from OLD. > > I wonder is it posible to achieve whithout precalculating vector of NEW > indexes, just by calculating new value from given pat and old index? > > Thanks in advance, > Mikl > > -- > Mikl > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
