VK said:
It has been observed that javascript should theoretically be capable of
emulating anything. A reasonable criteria for deciding whether a
language that can emulate anything "has" something specific might be to
examine how that something could be achieved with the language and
distinguish between the things that need to be emulated and those that
do not. With the things that do not need to be emulated being the things
that the language does "have".
None of the items listed above can be employed in javascript without
code being authored in order to emulate them. So javascript does not
"have" any of them.
(besides there is not "hash array" as a proper term.
It is a bit hypocritical of you to quibbling about terms when you more
often as not use terms in a way that is unique to you.
One should say "associative array", "hashtable" or "hash")
But one should only use those terms when referring the three distinct
things that are associative arrays, hashtables and hashes. They are
certainly not interchangeable terms for the same thing, and arguably
inapplicable to any native feature of the javascript language.
Let's stop on the first wrong.
Yes lets. The initial wrong statement you made, and repeated, was:-
| I repeat my very first statement: "JavaScript Array is
| dynamic, jagged, sparse"
There is no question that the javascript Array is dynamic. You can add,
remove and assign new values to the properties of a javascript Array at
any time. All javascript arrays exhibit dynamicness, it is a fundamental
characteristic of the javascript array.
There is no question that the javascript Array is a sparse array. Even
javascript Array instances that are not sparse themselves can be
rendered sparse by deleting some of their 'array index' properties or
assigning bigger values to their - length - property. All javascript
Arrays are capable of exhibiting sparseness, it is a fundamental
characteristic of all javascript Arrays.
But 'jagged' is not an appropriate characteristic to apply to the
javascript array. It is logically impossible for a javascript Array to
exhibit jaggedness, it is _not_ a characteristic of the javascript
array at all.
You are still i) refusing to read the definition
The definition of what exactly? Would that have been the definitions of
a 'jagged array' that you posted without stating their sources? The
first read:-
| <quote>
| We are using the term "jagged array" to describe a
| multi-dimensional array that is not necessarily rectangular.
| ...
- with a rather contradictory second alternative reading:-
| <quote>
| The jagged array is basically an array of arrays.
| ...
Obviously as javascript Arrays only have a single dimension that first
definition effectively says that a javascript Array is not a 'jagged
array', and as a javascript Array is not an array or array the second
definition states that a javascript array is not a 'jagged array'. So
under those circumstances it is difficult to see what relevance these
definitions have to the question in hand, except to reinforce the
conclusion that it is incorrect to characterise the javascript Array as
'jagged'. A conclusion that requires no reinforcement as it is a logical
consequence of a true statement about javascript, therefor itself true.
ii) thinking of a particular array instead of the model.
If you want to make a statement about the nature of the javascript Array
the inability to show any javascript array instances exhibiting
jaggedness is a telling factor in deciding whether jaggedness is a
characteristic of the javascript Array. Saying that no javascript Array
instance exhibits jaggedness is not "thinking of a particular array", it
is a general statement about javascript Arrays.
var myArray = new Array();
myArray[0] = new Array(1,2,3,4);
myArray[1] = new Array(1,2,3);
myArray[2] = new Array(1,2);
myArray[3] = new Array(1,2,3,4);
myArray is a sigle-dimension array.
As are all javascript Arrays.
But it has other arrays as its elements.
It certainly does. The structure created here is an array of arrays.
In the programming it is called "jagged array".
It corresponds with your second quoted definition of a 'jagged array',
and contradicts the first as it is not a multi-dimensional array (except
as an emulation of the multi-dimension concept executed with javascript;
an array of arrays).
I intentionally took different size arrays to show why
the word "jagged" had been chosen.
Redundant as that has not been significantly disputed.
It again doesn't imply that internal arrays *have* to
be of different size.
They do if you want to call this a 'jagged array'.
They can perfectly be of the same size.
If they were the same size your could only call this a multi-dimensional
array (as that would be the concept that would be being implemented in
that case, there would be no jaggedness to justify the term 'jagged
array').
It's again not a description of a particular
instance, but abstract model
No that is a particular instance. It is an instance of something that
implements the concept of a 'jagged array' as described by the second of
your quoted definitions.
thinking: this kind of array *can* be jagged, so it is always
called "jagged" to destinguish from "multi-dimensional" array
which cannot be jagged.
On the contrary, a 'jagged array' must be a multi-dimensional array. The
first of your quoted definitions stated as much, and the emulation of a
multi-dimensional array in javascript is just as much an array of arrays
as your example of an emulation of a jagged array. The jaggedness of a
jagged array follows from the non-rectangularness of a multi-dimensional
array. With a single dimension there would not be the variation that is
described a jagged, and indeed there would be nothing else to have
variation between.
You are welcome to print out myArray sample and go
across the world (both European and American institutes
are welcome) asking for definition and explanation. It
will be the same I just gave you.
Your code is already understood, it is just irrelevant to the question
at hand. It is irrelevant because a javascript Array is not an array of
arrays. Choosing to call a particular form of an array of arrays a
'jagged array' does not imply anything about things that are not arrays
of arrays, and the javascript array is not an array of arrays.
The only justification that can be made for "JavaScript Array is
dynamic, jagged, sparse" is to show a (any) javascript Array instance
exhibiting jaggedness (which is a proven impossibility). You can either
do that or your characterisation of javascript Arrays is just false.
Richard.
