I have a function that I want to use to demonstrate flipping a coin 100 times:
function simulateFlips(n, pHeads){
var head_count = 0;
var H;
for(var i=0; i < n; i++){
H = 0;
if (Math.random() < pHeads){
H = 1;
}
head_count += H;
}
return head_count;
}
However, it looks like the standard Google App Behavior is to "memoize" custom functions that are called with exactly the same inputs, which is not what you want for this kind of demo:
I know I could do something hacky (like modify pHeads by a very small amount), but I was hoping there was some cleaner way to get the desired behavior.
Here's the explanation of this behavior:
Script to summarise data not updating
Read the comments to see suggestions on how to workaround it.
Pass a second param in that you ignore but which is different for each line.
Related
Hi something simple is annoying me and I'd like some help!
function highlight(textField:TextField):void
{
var l:int = textField.text.length
for(var i:int = 0; i < l; i++)
if (!highlightChar(textField, i))
l++;
}
This loops through a character string to add a box behind the character for a highlighter affect. Some of the characters fail (the bounding box is null, assume these are returns etc) and in the example I'm looking at it returns false 5 times, and the boxes are 5 characters short. I'm attempting to add another iteration when it fails to keep going for another 5 characters, but this loop never stops.
Is there another way of doing this?
Hacky solution - collecting the fail count and then doing another loop after the first one finished has fixed it
if(fails > 0)
for(var f:int = i; f < fails + i; f++){
var box:Shape = highlightChar(textField, f);
if(box) boxes.addChild(box)
}
If I assign a Vector like
var vec1:Vector.<Number> = new Vector.<Number>(3);
vec1 = (1,2);
the result of vec1.length is 3. Is there any built-in method to return the number of the elements actually present in the vector?
I'm an ActionScript noob so any help would be appreciated.
Well you can solve your problem by creating an empty vector instead of a defining the vector size at the time of its declaration and then you gradually add and remove elements to the vector. In this way you will always get the total number of elements inside the vector when you call vector.length
For example:
var vec1:Vector.<Number> = new Vector.<Number>();
vec1.push(5);
vec1.push(6,7);
vec1.pop();
Then vec1.length would give you 2.
Its been awhile, heres the reference: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/Vector.html
I believe the .length is the normal way to check its length. If you want to check for "empty elements" you will need to loop through it with a loop.
I don't remmember the exact syntax, but to loop, do something like:
int count = 0;
for (int i = 0; i < vec.length; i++) {
if (vec[i] == ... );
count++;
}
I'm trying to work out a way for my game to recognise when two instances of this array have the same x or y position as another and if so to move re randomize the position of one of the instances.:
for(i=0;i<8;i++) {
PlatformInstance[i] =new Platform();
PlatformInstance[i].y= Math.random()*900;
PlatformInstance[i].x= Math.random() *1500;
stage.addChild(PlatformInstance[i]);
}
the problem i have is that the code i try detects that one platform instance has the same position as the SAME platform instance, and will constantly re randomize the position.
is there a way to differentiate between different instances?
thanks very much in advance.
EDIT
The only code i could think of was running an if statement in a loop to see whether
If (PlatformInstance[i].y == PlatformInstance[i].y)
Obviously this wouldnt work and thinking of it i know it wouldn't however i was wondering if there was a way to do:
If (Platforminstance[i].y == "other" Platforminstance[i].y
or some other words to that effect
You don't seem to have a clear understanding of how arrays work, I recommend looking into that. Something like this should work
i=0;
j=0;
while( i < PlatformInstance.length -1) {
j++;
if (j == PlatformInstance.length) {
i++;
j=i+1;
}
if( (Math.abs(PlatformInstance[i].x - PlatformInstance[j].x) < platformWidth)
|| (Math.abs(PlatformInstance[i].y - PlatformInstance[j].y) < platformHeight) ) {
PlatformInstance[j].y= Math.random()*900;
PlatformInstance[j].x= Math.random() *1500;
//Now you'll have start checking at the beginning again since you moved one
i=0;
j=0;
continue;
}
}
Also as it was previously mentioned, PlatformInstance is not a good name for an array. Only Class names should start with a capital letter. And an array of platforms should not be called an "instance". I would recommend changing it to simply platforms
How do I replace the selected pixel of the image? I used set pixel and get pixel concept but not getting the desired effect.
http://www.digital-photography-school.com/wp-content/uploads/2009/07/before-after.jpg
var s_color = 0x0083C7;
color_picker.addEventListener(ColorPickerEvent.CHANGE, changeColor);
function changeColor(ColorPickerEvent)
{
var _color = color_picker.selectedColor.toString(16);
var color = String("0x"+_color);
for (var j = 0; j <m_inputImage.width; j++)
{
for (var k = 0; k < m_inputImage.height; k++)
{
if (m_inputImage.getPixel(j,k)== s_color)
{
m_inputImage.setPixel(j,k,color);
}
}
}
s_color = color;
}
I want similar type effect.
Please guide me.
This is not a job for BitmapData, you should use Pixelbender for this.
http://www.adobe.com/devnet/flash/articles/pixel_bender_basics.html
You can find all shaders here, there are a lot of hue/saturation and color manipulation filters so pick one that suits you the best.
http://www.adobe.com/cfusion/exchange/index.cfm?event=productHome&exc=26&loc=en_us
I would use Photoshop instead of Flash to achieve the effect you desire.
However Photoshop is kind of expensive, so I would use the Bitmap class in conjunction with the BitmapData class and use an algorithm to run through each pixel and check for a certain threshold of red and convert it to the right threshold of yellow. If you would post the code you already have written I could possibly add to it, I'm not going to spend the next hour writing an example though.
So let's say i have T, T = 1200. I also have A, A is an array that contains 1000s of entries and these are numerical entries that range from 1000-2000 but does not include an entry for 1200.
What's the fastest way of finding the nearest neighbour (closest value), let's say we ceil it, so it'll match 1201, not 1199 in A.
Note: this will be run on ENTER_FRAME.
Also note: A is static.
It is also very fast to use Vector.<int>instead of Arrayand do a simple for-loop:
var vector:Vector.<int> = new <int>[ 0,1,2, /*....*/ 2000];
function seekNextLower( searchNumber:int ) : int {
for (var i:int = vector.length-1; i >= 0; i--) {
if (vector[i] <= searchNumber) return vector[i];
}
}
function seekNextHigher( searchNumber:int ) : int {
for (var i:int = 0; i < vector.length; i++) {
if (vector[i] >= searchNumber) return vector[i];
}
}
Using any array methods will be more costly than iterating over Vector.<int> - it was optimized for exactly this kind of operation.
If you're looking to run this on every ENTER_FRAME event, you'll probably benefit from some extra optimization.
If you keep track of the entries when they are written to the array, you don't have to sort them.
For example, you'd have an array where T is the index, and it would have an object with an array with all the indexes of the A array that hold that value. you could also put the closest value's index as part of that object, so when you're retrieving this every frame, you only need to access that value, rather than search.
Of course this would only help if you read a lot more than you write, because recreating the object is quite expensive, so it really depends on use.
You might also want to look into linked lists, for certain operations they are quite a bit faster (slower on sort though)
You have to read each value, so the complexity will be linear. It's pretty much like finding the smallest int in an array.
var closestIndex:uint;
var closestDistance:uint = uint.MAX_VALUE;
var currentDistance:uint;
var arrayLength:uint = A.length;
for (var index:int = 0; index<arrayLength; index++)
{
currentDistance = Math.abs(T - A[index]);
if (currentDistance < closestDistance ||
(currentDistance == closestDistance && A[index] > T)) //between two values with the same distance, prefers the one larger than T
{
closestDistance = currentDistance;
closestIndex = index;
}
}
return T[closestIndex];
Since your array is sorted you could adapt a straightforward binary search (such as explained in this answer) to find the 'pivot' where the left-subdivision and the right-subdivision at a recursive step bracket the value you are 'searching' for.
Just a thought I had... Sort A (since its static you can just sort it once before you start), and then take a guess of what index to start guessing at (say A is length 100, you want 1200, 100*(200/1000) = 20) so guess starting at that guess, and then if A[guess] is higher than 1200, check the value at A[guess-1]. If it is still higher, keep going down until you find one that is higher and one that is lower. Once you find that determine what is closer. if your initial guess was too low, keep going up.
This won't be great and might not be the best performance wise, but it would be a lot better than checking every single value, and will work quite well if A is evenly spaced between 1000 and 2000.
Good luck!
public function nearestNumber(value:Number,list:Array):Number{
var currentNumber:Number = list[0];
for (var i:int = 0; i < list.length; i++) {
if (Math.abs(value - list[i]) < Math.abs(value - currentNumber)){
currentNumber = list[i];
}
}
return currentNumber;
}