Since d. /D. are being retired (for derivative usage), why not use them for an
inbuilt dictionary type?
I think J would be better with some kind of hashmap / dictionary (O(1) lookup
time), and d./D. already match
the first letter of "dictionary", so it's the perfect fit.
On Monday, November 18, 2019, 12:25:27 PM GMT+9, bill lam
<[email protected]> wrote:
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
> ><[email protected]>:
> > 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 <
> > [email protected]> 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 <
> > > [email protected]>:
> > >
> > > 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 <[email protected]>
> > > 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
> > > > ----------------------------------------------------------------------
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> > > >
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> > >
> >
>
> ----------------------------------------------------------------------
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--
regards,
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