[Jprogramming] J and data structures

['Mike Day' via Programming]

It's a long time since I played with s:  - do J symbols have any 
relevance to dictionaries/directories?

APL/J cousin, K, appears to have the dictionary as pretty central to its 
data organisation, but maybe
that's more akin to J's locales.

Neither topic helpful probably relevant here,  but might start a hare!

Mike

On 18/11/2019 02:49, Henry Rich wrote:
> 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 <devonmcc at 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 <
>> programming at 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 <
>>> rauldmiller at 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.gauvin at 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
>>>> ----------------------------------------------------------------------
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>>>>
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>>>
>>
>
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