Comments on: A strange way AS3 manages arrays

By: Thi

Thi — Wed, 19 Aug 2009 20:09:50 +0000

var one:Array = [[1],[2],[3]]
var two:Array = one.concat()

two[0] = two[0].concat() //weird thing
two[0][0] = 4

trace(one, two) // 1,2,3 4,2,3

that shold resolve the array in array thing ^^

By: Mauro

Mauro — Tue, 07 Apr 2009 16:45:33 +0000

ok he was just showing something he thought was curious, why are you guy blaming him?

remember, not even a PROgrammer knows all tricks!

By: mark

mark — Sun, 28 Dec 2008 18:32:55 +0000

lol… public function wtf(){

By: Michael Boucher

Michael Boucher — Sat, 27 Dec 2008 22:32:03 +0000

With PHP you explicitly tell a variable to pass by reference. If I remember correctly this is done as follows:

// Changes to $myArr2 no affect on $myArr1
$myArr2 = $myArr1;

// Changes to $myArr3 affect $myArr1
$myArr3 = &$myArr1;

Agreed that concat() should be used for “copying” an array and breaking the reference. Can’t find the posting with some speed tests but concat() proved to be the fastest method.

Have to somewhat disagree that PHP offers a poor design decision on how it assigns complex types. It’s all a matter of the “default” for both languages, PHP doesn’t lack the ability to assign by reference, it just isn’t the default behavior.

Best,
-michael

By: vitaLee

vitaLee — Sat, 27 Dec 2008 22:24:56 +0000

the only problem here was that you approached this situation with wrong expectations.
your php background experience didn’t help you here.
i’ve once felt in this kind of situation and then i found out about the concat method.
HEAD UP !!! :)

By: Sudoku creator/solver with AS3 : Emanuele Feronato

Sudoku creator/solver with AS3 : Emanuele Feronato — Sat, 27 Dec 2008 13:10:23 +0000

[...] after a little hassle due to a strange way AS3 manages arrays (in my opinion), I am ready to post the AS3 version of the [...]

By: Michael Kaufman

Michael Kaufman — Sat, 27 Dec 2008 07:57:59 +0000

Exactly, since you made a custom object you are sharing a reference. Really has nothing to do with Arrays and just the way AS handles variable assignments for anything except String, Boolean, Number, int, and uint. I did not know PHP treats assignments differently. Good to know. Thanks :)

[code]
var aNum:uint = 0
var bNum:uint = aNum

trace (aNum) //0
trace (bNum) //0

aNum = 2
trace (aNum) //2
trace (bNum) //0
[/code]

By: colbycheeze

colbycheeze — Sat, 27 Dec 2008 03:57:39 +0000

I had this confusing issue once before, and it took a while to figure it out.

I thin it is actually much better this way however, so I am glad it does it.

I do wish you could pass primitives as reference like in C++ however…

By: Jason Reid

Jason Reid — Sat, 27 Dec 2008 03:51:41 +0000

Yeah, this is really a PHP thing. Most languages (Javascript included) work more like the way that AS3 does.

C doesn’t have built-in push / pop operators on it’s arrays, so its behavior would depend on whatever libraries you were using for list management.

By: Daniel Rodriguez

Daniel Rodriguez — Sat, 27 Dec 2008 00:00:05 +0000

That remembers me a day I almost died with a project in java, it happens something similar.