Arrays: new and old keys, i

[Richard Gaskin]

David Bovill wrote:

> 2008/9/14 Richard Gaskin <ambassador at fourthworld.com>
>> For accessing specific elements from large collections, arrays outperform
>> any lineoffset in lists or any other method I can think of by several orders
>> of magnitude.*
>>
>> Read, "It's a good hash mechanism". :)
>>
>> When I need ordinal sequential access, I use ordinal keys.  Am I some sort
>> of freak?
>
> Most of the time I need both with the same data - classic example would be
> paragraphs of text with indented titles (an outline index) - or a tree of
> objects and their properties. I want the data in a way in which I can
> interact with the keys (titles in a hierarchical structure) - and display or
> process the data (say a paragraph of text) asociated with that key.
> 
> Order sometimes does not matter = click display paragraph  - but often does
> = reconstruct document. In short I want a simple data model which does both.
> With sequentially ordered array keys we would have that.

I do a similar thing with processing sections of HTML in WebMerge, where 
I need to grab a page section with in a tag, do a lot of stuff with it, 
and tuck it back into that space to generate the final output.  For 
those I use simple ordinal keys, and it's worked a treat for years.

Your case differs in that each element has two distinct things to keep 
track of: title and body.

In the olden days (pre v3) you might consider just using two arrays to 
retrieve the title and body for a given ordinal element:

   put tMyTitleA[5]
   put tMyBodyA[5]

In v3 it seems simple enough to use a single array by just having it use 
ordinal keys at its outermost level, and the elements within it are each 
their own two-element array, with their keys being "title" and "body", 
allowing you to instantly retrieve either for a given item easily:

   put tMyData[5]["title"]
   put tMyData[5]["body"]

- or -

   put tMyData[5] into tMySnippetA
   put tMySnippetA["title"]
   put tMySnippetA["body"]


Are there cases where putting your arrays inside of ordinal wrapper 
arrays would be problematic?

-- 
  Richard Gaskin
  Managing Editor, revJournal
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