key/value dictionary can be done in addon, but I think better implemented in C for efficieny because it contains loops.
Sun, 17 Nov 2019, Henry Rich написал(а): > In J I find myself coming back to simple arrays for most data structures. > > Trees can be represented as boxes containing subtrees. That works, but is > usually more trouble than simply managing an array. > > Linked lists are used only for efficiency, and in the cases where that > matters you can easily have a list of indexes to an array of data items. > > Stacks are just lists, as Devon said. > > The datatype I really want is a directory object that acts as an efficient > and easy-to-use associative memory. You put key/values in and then retrieve > a value by presenting its key. Has anyone written an addon for that? > > (Note: the primitive 128!:8 (create a hash for a noun) was added to J9.01 > with this in mind) > > Henry Rich > > On 11/17/2019 8:16 PM, 'Bo Jacoby' via Programming wrote: > > I failed to communicate the links before, but here they are. Ordinal > > fractions are somewhat like infinite-dimensional arrays. > > https://www.academia.edu/10031088/ORDINAL_FRACTIONS_-_the_algebra_of_data > > > > > > http://www.statemaster.com/encyclopedia/Ordinal-fraction > > Bo. > > > > Den søndag den 17. november 2019 22.07.28 CET skrev Devon McCormick > > <devon...@gmail.com>: > > Trees are simple to implement in J - > > https://code.jsoftware.com/wiki/User:Devon_McCormick/Trees - as are graphs > > - > > https://code.jsoftware.com/wiki/NYCJUG/2009-11-10/BreadthFirstGraphTraversal > > . > > A stack is simple to implement too but I'm not sure why you would want to > > as it's simply a vector with very restrictive rules to manipulate it. > > Linked lists make no sense in a language with dynamic arrays for much the > > same reason since a linked list is mainly a way of implementing dynamic > > arrays but has benefit only in a language which lacks these natively. > > > > On Sun, Nov 17, 2019 at 8:24 AM 'Bo Jacoby' via Programming < > > programm...@jsoftware.com> wrote: > > > > > ORDINAL FRACTIONS - the algebra of data > > > > > > > > > > > > | > > > | > > > | > > > | | | > > > > > > | > > > > > > | > > > | > > > | | > > > ORDINAL FRACTIONS - the algebra of data > > > > > > This paper was submitted to the 10th World Computer Congress, IFIP 1986 > > > conference, but rejected by the referee.... > > > | > > > > > > | > > > > > > | > > > > > > > > > > > > > > > Den søndag den 17. november 2019 07.12.02 CET skrev Raul Miller < > > > rauldmil...@gmail.com>: > > > > > > Arrays are roughly analogous to computer memory. > > > > > > Put different: I think you are asking the wrong question. > > > > > > (Partially: it's worth thinking about why you pick whichever data > > > structures...) > > > > > > ((It can also sometimes be useful to look on rosettacode for examples of > > > various daya structure handling mechanisms.)) > > > > > > Thanks, > > > > > > -- > > > Raul > > > > > > On Sat, Nov 16, 2019 at 6:00 PM Jimmy Gauvin <jimmy.gau...@gmail.com> > > > wrote: > > > > > > > Hi, > > > > > > > > when dealing with data structures other than arrays such as trees, > > > graphs, > > > > stacks, linked lists what other programming language do you resort to ? > > > > > > > > Or do stick with J for all endeavours? > > > > > > > > > > > > Jimmy > > > > ---------------------------------------------------------------------- > > > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > > > ---------------------------------------------------------------------- > > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > > ---------------------------------------------------------------------- > > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm -- regards, ==================================================== GPG key 1024D/4434BAB3 2008-08-24 gpg --keyserver subkeys.pgp.net --armor --export 4434BAB3 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
