What's wrong with Multidimensional Array?

--- Example 1
var myarray=[[],[]];
myarray[0][1]="NA"
print(myarray[0][1]); // output "NA"

--- Example 2
var myarray=[[],[]];
for (var x = 0; x < 5; x++) {
for (var y = 0; y < 5; y++) {
myarray[x][y]=0;
}
}

for (var x = 0; x < 5; x++)
print(myarray[x]); // output error myarray[x] is undefined !?!

What's wrong with example 2 ????

 

--- Example 1.1
var myarray=[[],[]];
myarray[10][10]="NA"
print(myarray[10][10]); // output error myarray[10] is undefined

OMG What a mistake-a to make-a.
Thank you!

[snip]

OK, I see it now.
But I'm curius, is it possible to create empty multidimensional array in
advance?

 

Thank you very much for your help.

 

Given that, according to my current research, Array comprehension is *only*
supported in (Mozilla) JavaScript 1.7 and later, I do not think it deserves
the attribute "portable" at all.


PointedEars

 

Thomas 'PointedEars' Lahn wrote on 20 feb 2012 in comp.lang.javascript:

I fail to comprehend the meaning of such atributable comprehension, Thomas.

Could you divulge?

 

In comp.lang.javascript message <irp1k7puv7pgmuhuuhnpovq6dolg7pubea@4ax.

One can assign a value to a variable which does not already exist.

For counting purposes, it would be useful to be able to increment a
variable which currently is value=undefined or is non-existent, with the
pre-increment value taken as either 0 or "", depending on the nature of
the increment. Possibly with X+++ and X ++= 7.

 

<https://developer.mozilla.org/en/JavaScript/Guide/
Predefined_Core_Objects#Array_comprehensions>

-- Scott