Array problem: has no properties - why?

[Randell D.]

Folks

I have a multi-dimensional array in javascript, as follows:

gameRecord=new Array(500);
gameRecord[1][1]="FA Cup : 19 February 2005";
gameRecord[1][2][1]="Arsenal v Sheff Utd, 12:30";
gameRecord[1][2][2]="Bolton v Fulham, 15:00";
gameRecord[1][2][3]="Charlton v Leicester, 15:00";
gameRecord[1][2][4]="Everton v Man Utd, 17:30";
gameRecord[1][2][5]="Southampto n v Brentford, 15:00";

There are alot more records to it, but the above is just an extract...
It is written into its own javascript file (called football.js) which I
call using

<script language="JavaS cript" type="text/javascript"
src="football.j s"></script>

I know its reading it because for a test, I preceeded the file with a
simple alert("here"); and this shouted back at me.

How come though that even before I read from the array I get the
following error message in the JavaScript Console in Mozilla...

Error: gameRecord[1] has no properties

I gather I am initializing the array incorrectly - would someone care to
direct me in the right direction?

Thanks
Randell D.

[Douglas Crockford]

>> I'm glad to hear about the 'zero element' because my array did

(incorrectly) begin with 1, and not zero.

Well, as RtS said, you can define entries at any index you like.
However, you must remember that the elements you skip still exist (to an
extent). The length property is updated to reflect the highest index
plus one. So assigning values to elements 3, 5, 9 will result in a
length of ten (*not* nine, as you thought). The other seven elements
will remain undefined.

In JavaScript arrays, the numeric indexes are converted to strings, so

my_array[0]

and

my_array['0']

reach the same element. It is not like a traditional array that has a
linear sequence of numbered slots. You can think of JavaScript arrays as
being sparce arrays: only slots with values consume memory.

The value of a missing element is undefined.

http://www.crockford.com/javascript/survey.html

[Dr John Stockton]

JRS: In article <59************ *************** @msgid.meganews servers.co
m>, dated Sun, 20 Feb 2005 08:04:58, seen in news:comp.lang. javascript,
Douglas Crockford <no****@covad.n et> posted :

In JavaScript arrays, The value of a missing element is undefined.

That's either ambiguous or wrong, considering it on its own; and,
considering its author, it cannot be wrong.

The value of a missing element is defined, and it is defined as the
special value called undefined. That value itself is well-defined,
although its internal representation probably is not.

[][0] == [][1] evaluates, by definition AIUI, as the value true.
In discussing javascript, undefined should not be used to mean not-
defined; but, lest it be so misinterpreted, neither should it be used
unaided to mean what it rightly means.

--
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