Overloading Arrays for multi-dimensional purposes

[Flawless_koder]

VARIABLE1,VARIABLE1,PROPERTY1,PROPERTY2...PROPERTY6|\

You have a number of lines - in the above format.
They are in a single variable.
You want to take it
and create a multi-dimensional Array.
MORE than that - you want it more in an hash ( list, dictionary ) format.

I thought it couldn't be done in JS.
I finally hit a problem which i couldn't overcome without
working out how to handle this.

For anyone that doesn't know how these look:

[VARIABLE 1a]
    | - [VARIABLE 2a] = [ PROPERTY 1, PROPERTY 2 ...]
    | - [VARIABLE 3a] = [ PROPERTY 1, PROPERTY 2 ...]
    | - [VARIABLE 4a] = [ PROPERTY 1, PROPERTY 2 ...]
    | - [VARIABLE 5a] = [ PROPERTY 1, PROPERTY 2 ...]
[VARIABLE 1b]
    | - [VARIABLE 2b] = [ PROPERTY 1, PROPERTY 2 ...]
    | - [VARIABLE 3b] = [ PROPERTY 1, PROPERTY 2 ...]
    | - [VARIABLE 4b] = [ PROPERTY 1, PROPERTY 2 ...]
    | - [VARIABLE 5b] = [ PROPERTY 1, PROPERTY 2 ...]

Now you want to be able to access these by name but not
have multiples, and not overwrite the previous value.

The method I've ended up with looks like this:

MAKES = new Array();
TYPES = new Array();

var str='\
ECMN,AVIS,FORD,MONDEO,GREEN,1.5|\
ECMN,HERTZ,FORD,MONDEO,GREEN,1.5|\
ECAR,HERTZ,FORD,MONDEO,GREEN,1.5|\
';

var all = str.split(/\|/);

for (i=0;i<all.length;i++){
        var set = all[i].split(/,/);
        if (!TYPES[set[0]]){ TYPES.push(set[0]); TYPES[set[0]] = 1; }
        if (!MAKES[set[1]]){ MAKES.push(set[1]); MAKES[set[1]] = 1; }
        l=set[0]+"['"+set[1]+"']=new Array('"+set[2]+"','"+set[3]+"','"+set[4]+"','"+set[5]+"')";
        try { eval(l); }
        catch(e) { eval(set[0]+' = new Array();'); eval(l); }
        }

alert(eval(TYPES[1]+'["'+MAKES[1]+'"]'));
alert(MAKES);

Effectively this gives you the ablility to say:
alert ( ECMN['AVIS'] ) and you'll get an array returned
containing Ford Mondeo Green 1.5!

Now i don't know if i'm being stupid - but to me that
seems like a very slight breakthrough.

Am i rediscovering the wheel, and is there a common way of doing this?

Can anyone think of how to improve this?

Flawless

[Flawless_koder]

Now something I *hadn't* thought of was setting the
length of the array to be the name of the new array name.

That way - when you call ECMN.length - instead of returning
0 (although techically it pseudo holds four or so values) - it would return the number of true elements.
THAT way - you can then use ECMN to query what arrays
it holds as if it really were a multi-dimensional hash/list/dictionary - RATHER than just a multi-dimensional array.

The change is with the variable s and the evaluation of it:

<script language="Javascript">

MAKES = new Array();
TYPES = new Array();

var str='\
ECMN,Avis,Ford Mondeo 1.6,32.5,1|\
ECMN,Hertz,Vauxhall Astra 1.5,35.1,1|\
ECMN,Option,Vauxwagon Jetta 1.4,29.5,1|\
ECMN,Sixt,Lexus IS300,41.2,0|\
ECAR,Avis,Mercedez C200,42.1,0|\
ECAR,Hertz,BMW 318i,45,1|\
ECAR,Option,Vauxwagon Passat 1.5,27.1,1|\
ECAR,Budget,Ford Scorpio 1.8,37.2,1|\
ECAR,Sixt,Skoda Octavia 1.9,35.4,1|\
CDMN,Avis,Ford Focus 1.3,21.5,1|\
CDMN,Hertz,Peugeot 207 1.4,25.1,0|\
CDMN,Budget,Nissan Micra 1.1,16.1,1|\
CDMN,Option,Vauxhall Corsa 1.2,15.3,1|\
LDAR,Avis,Mercedez SLK 500,82,1|\
LDAR,Hertz,BMW 850csi, 95.2,0|\
LDAR,Sixt,Lexus GS 500, 89.2,1|\
';

var all = str.split(/\|/);

for (i=0;i<all.length;i++){
        var set = all[i].split(/,/);
        if (!TYPES[set[0]]){ TYPES.push(set[0]); TYPES[set[0]] = 1; }
        if (!MAKES[set[1]]){ MAKES.push(set[1]); MAKES[set[1]] = 1; }
        l=set[0]+"['"+set[1]+"']=new Array('"+set[2]+"','"+set[3]+"','"+set[4]+"')";
        s=set[0]+"["+set[0]+".length]='"+set[1]+"'";
        try { eval(l); }
        catch(e) { eval(set[0]+' = new Array();'); eval(l); }
        eval(s);
        }

var COMPANIES = new Array();
var COMPANIES = new Array();

COMPANIES['AVIS'] = new Array('image/r_avis.gif','#FFFFFF');
COMPANIES['HERTZ'] = new Array('image/r_hertz.gif','#EAEAEA');

alert(ECMN[ECMN[0]]);

You can see that with ECMN[ECMN[0]] we have direct access
to the array inside it by calling it's name
This allows our pseudo for:

for (i=0;i<ECMN.length;i++){
ECMN[ECMN[i]] << this recieves the array object.
}

NOW - we could either use the default "for variable in object" OR we could create our own constructer with a new function - and call it progressively - though that would
take a lot of work.

Is anyone interested in this at all?

Flawless

[beetle]

That's fantastic, but like you said...not sure if I have a valid application for it other than testing it on my machine and saying, "CL!"

What does catch() do?

[Flawless_koder]

Well no - i had a need for it - so i created it.

try {}
catch (e){}
is an error handling mechanism.

Flawless

[beetle]

so it works like this?

try { [...snippeta...] }
catch(e){ [...snippetb...] }

If 'snippeta' errors then run 'snippetb' and suppress the error.

Do I have that right?

[Flawless_koder]

yes - and e recieves the error.

There's more complexities to it if you need them...
but in this case i didn't.

Flawless

[Flawless_koder]

Rather than needing to create your own handler for the members - why not just use the for (obj in obj) statement - which isn't based on length!

This means we can run it with:
if (!CLASSES[set[0]]) CLASSES.push(set[0]);// CLASSES[set[0]] = 1; }
if (!COMPS[set[1]]) COMPS.push(set[1]);// COMPS[set[1]] = 1; }

Rather.

Flawless

[Flawless_koder]

or rather:

if (!CLASSES[set[0]]) CLASSES[set[0]] = 1; }
if (!COMPS[set[1]]) COMPS[set[1]] = 1; }

If you're doing it backwards ( name based )

Flawless

[Skunk]

Is there a way of doing that without using eval?

[Flawless_koder]

ummm - what can i say apart from "HUH?" ..

Which bit?

Flawless

[Skunk]

The code in your first post on this thread.

[Flawless_koder]

Oh - you mean - without evaluation the names...

Well:

set[0] in one iteration may = 'ECMN'

if you weren't to evaluate it - it would either
take set[0] as the value held in it - or the literal of
the name... either way - not what we'd want.

BUT - the only reason i'm doing it that way is because
i'm generating the arrays automatically.

If you weren't - then you're fine saying:

array['NAME'] = new Array( ARRAYREF1, ARRAYREF2 ... );

where ARRAYREFS are arrays to their own right.
That example takes it to a 4th dimension though - i think.

In this example you'd end up - for sure - with array.length
as 0. To iterate you'd have to use:

for (name in array)

and in that case name would recieve the literal value NAME -
so you'd have to then use:
array[NAME] - to pull up the array referenced - and then indexing ( or a second level of naming ) to pull up the 3rd or 4th dimensions respectively.

Flawless

[MarcusJT]

lol! How spooky - earlier today I used the "for x in y" statement to finally create a neater solution to my character entity problem than what I was originally going for!!! :-)

[Andrew-J2000]

oh post that up, so you actually got a fix for that thing then M@rco

[Andrew-J2000]

oh and flawless, you should post somemore of your stuff that you've done, i'm sure others will think HTFDHDT (How The F@ck Did He Do This). As i'm still trying to work it out on things like the wire meshes for 3d graphics etc.

[Flawless_koder]

*blush*

Why thank you Andrew.

I'll post some stuff every now and then.

Flawless

[MarcusJT]

Andrew - it's not a fix, but it is a better overall solution (in the end) than my original approach. I'll "post up" !!!!

[Flawless_koder]

Marco - can we take a look at a real fix for your problem then... if you haven't yet found one?

Flawless

[MarcusJT]

I've posted the code in that thread:
http://www.sitepointforums.com/showt...threadid=67869

[MarcusJT]

And get my name right! It's short enough!

[Flawless_koder]

Fixed - - Sorry about that.

I'm SURE i've heard the second part of that expression before...
...

"Why can't you get it in first time - it's short enough!"



he he

Flawless

[MarcusJT]

Indeed! lol
(I don't like to brag, but I've never encountered that problem myself! )

[Flawless_koder]

You see i always thought that the suit must have been
making up for something

Flawless