flash actionscript: Hey there,

Not sure if this has already been answered, because I think I saw it a really
long time ago.

I'll make it very simple. I have an array and I want to, based on the arrays
length, make a new array and randomize the order that all the numbers in the
new array will be in.

So lets say this is my array

var test_arr:Array = new Array();
test_arr = [40, 80, 120, 160, 200, 240]

And after I send it through the, say jumbleArray() function, it comes back
with a new array, looking like this

new_arr = [160, 240, 80, 200, 40, 120]

Any help here? Thanks!!!

Craig Grummitt! Dude, you're a genius. Your code makes a lot more sense; I can
actually read it and totally understand what's going on. On the other shuffle
function, it didn't make complete sense.

I'll put it in a class file, I was just wondering if I could insert the
actionscript in some file that Flash always has, so I don't have to import
classes. Something like the Array class is built in and always there, and I was
wondering if I could put the code into that native class.

Thanks,

Sam

Whoops! Nevermind... I should have searched before I posted.

Does anyone know a way that I could make this so that it is a function I can
use in any of my flash documents? Like, is the some actionscript that is in a
special directory that I could insert it in? Let me know, that'd be great.
Thanks

Array.prototype.shuffle = function() {
var myArray:Array = new Array();
for (i=0; i<this.length; i++) {
var control:Boolean = true;
while (control) {
j = int(random(this.length));
if (myArray[j] == undefined) {
myArray[j] = this[i];
control = false;
}
}
}
return myArray;
};

you can place this code in a class and call it up when you need it.

i think the following line:
myArray[j] = this;
should be:
myArray[j] = this[i];

I find this way nice, succinct and less processor heavy than the way you
posted:

Array.prototype.shuffle = function() {
var oldArray:Array = this;
var newArray:Array = new Array();
while (oldArray.length>0) {

newArray.push(oldArray.splice(Math.round((oldArray.length-1)*Math.random()),
1));
}
return newArray;
};

Sam,

[quoted text, click to view]

You don't have to import classes in ActionScript 2.0. By adding the
path to this class file to your global classpaths setting, it will always
just "be there." In AS2, import isn't required ... it's just a convenience
that allows you to omit package names.

http://www.communitymx.com/content/article.cfm?cid=197DE

[quoted text, click to view]

I wonder if you're thinking about prototyping. If so, that's an AS1
approach, and only affects the prototyped classes in the current SWF
(meaning, you have to type in the code that prototypes the desired class
every time, or #include it).


David
stiller (at) quip (dot) net
Dev essays: http://www.quip.net/blog/
"Luck is the residue of good design."

Sam,

[quoted text, click to view]

I'm with ya. Or even just ...

var test_arr:Array = new Array(1, 2, 5, 6, 7, 8);
test_arr.shuffle();

And you *can* do that with the Object.prototype property, inherited by
all objects, of course. But you'd have to type (or #include) the
ActionScript that defines the prototyped method every time.


David
stiller (at) quip (dot) net
Dev essays: http://www.quip.net/blog/
"Luck is the residue of good design."

Ok, I totally understand what you're saying David. I was just wondering if
there's a way I could use it as if it were part of the array class. So I could
just simply do this

var test_arr:Array = new Array(1, 2, 5, 6, 7, 8);
var shuffled_arr:Array = test_arr.shuffle();

And those would be the only two lines of code in my actions frame. I don't
want to have to do

var shuffled_arr:Array = new com.sdpurtill.ShuffleArray(test_arr);

Understand? Thanks,

Sam

Sorry I don't have anyway for it to magically become part of every file, but
the following will be even less processor heavy than the splice technique.
We've tested it a lot and this is the fastest way to shuffle an array. So if
and when you find the way that you are going to implement this you might want
to base whatever you do off of this algorithm. :)

Array.prototype.shuffle = function() {
for (var i = this.length-1; i>0; i--) {
var p = random(i+1);
var t = this[i];
this[i] = this[p];
this[p] = t;
}
};
ASSetPropFlags(Array.prototype, "shuffle", 1, 1);

Thanks David and Rothrock.

One more question, to Rothrock... Did you forget a line of code?

//
return this;
//

Array.prototype.shuffle = function() {
for (var i = this.length-1; i>0; i--) {
var p = random(i+1);
var t = this[i];
this[i] = this[p];
this[p] = t;
}
return this;
};
ASSetPropFlags(Array.prototype, "shuffle", 1, 1);

And what is the ASSetPropFlags for?

Thanks,

Sam

No. I didn't forget a line. I use it just like this:

myArray.shuffle();

That will shuffle the array ? in place as it were. I guess adding the return
isn't a bad idea, but then you will end up with two shuffled arrays. And
because flash duplicates arrays by reference you might find a few surprises
down the line.

The ASSetPropFlags is used to "hide" the new prototype from the tyranny of the
for?in construction.

Create an array and do this:

for(a in myArray){
trace(a+" is "+myArray[a])
}

Try it both with that line and with that line commented out. I think the
benefits will be clear.