I am making a pretty neat quiz-game in flashCC right now and I definitely need your help.
My skills are more on the design then the programming side. So to many of you this might seem a baby question (and asked many times before) but from all the answers I saw so far, I couldn't get any results for my project.
So here is the thing :
I need the EXACT script for creating an array (with movieclips inside? or instance names of mcs? How does this even work?)
and a method, to pick a random element of this array without repeats until the "game is over".
Paul
The easiest way to pick a random element from an array without repeating is to first sort the array with a "random" function, then pop or shift items out of it until the array is empty.
Let's say you have an array of items which can be filled with either instances or instance names, you've chosen instance names: :
var FirstArray:Array = ["blau", "orange", "green"];
Now, you'll need a random sort function:
// you do not need to modify this function in any way.
// the Array.sort method accepts a function that takes in 2 objects and returns an int
// this function has been written to comply with that
function randomSort(a:Object, b:Object):int
{
return Math.random() > .5 ? -1 : 1;
}
The way a sort function normally works is it compares two objects and returns -1 if the first item precedes the second item, 1 if the opposite is true, and 0 if they are the same.
So what we're doing in the function above is returning -1 or 1 randomly. This should get the array all jumbled up when you call:
FirstArray.sort(randomSort);
Now that the array is randomly sorted, you can begin pulling items from it like so:
if(FirstArray.length) // make sure there's at least one item in there
{
// since you are using instance names, you'll need to use that to grab a reference to the actual instance:
var currentQuizItem:MovieClip = this[FirstArray.pop()];
// if you had filled your array with the actual instances instead, you would just be assigning FirstArray.pop() to currentQuizItem
// every time you call pop on an array, you're removing the last item
// this will ensure that you won't repeat any items
// do what you need to do with your MovieClip here
}
else
{
// if there aren't any items left, the game is over
}
When strung together, the above code should be enough to get you up and running.
You could try something like:
var array:Array = [1, 2, 3, 4, 5];
var shuffledArray:Array = [];
while (array.length > 0)
{
shuffledArray.push(array.splice(Math.round(Math.random() * (array.length - 1)), 1)[0]);
}
trace('shuffledArray: ', shuffledArray, '\nrandom item: ', shuffledArray[0]);
Related
I generally find indexOf very useful, to get an index directly, and not writing 3-4 lines of for loop to get a match.
Is there any similar function, say like indicesOf , to get an array of all possible matches ?
Or may be having a different name, but acts as a shortcut as beautifully as "indexOf" ?
As you don't mind creating a new Array, you can use the filter() function - it executes a function on each item of the array, then returns a new Array with the items that return true:
// our comparison function
function myCompFunction( element:*, index:int, array:Array ):Boolean
{
return ( element > 10 );
}
var ar:Array = [5,10,15,20];
var ar2:Array = ar.filter( myCompFunction ); // ar2 is now [15,20]
It's not exactly indicies, but then again, you don't need to dereference your objects.
NOTE: because it's calling a function on each element, looping through the array yourself will still be quicker
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/Array.html#filter()
Unfortunately, there is not such shortcut. indexOf works for only one item, and there is no alternative for multiple items.
The solutions are obvious - iterate over the entire array or use some kind of sort on the array. Maybe there are other methods, but they are almost the same - loop through everything and check. Sorry to say it, but that's the way it is :)
I guess a step back is in order. My original question is at the bottom of this post for reference.
I am writing a word guessing game and wanted a way to:
1. Given a word length of 2 - 10 characters, randomly generate a valid english word to guess
2.given a 2 - 10 character guess, ensure that it is a valid english word.
I created a vector of 9 objects, one for each word length and dynamically created 172000
property/ value pairs using the words from a word list to name the properties and setting their value to true. The inner loop is:
for (i = 0; i < _WordCount[wordLength] - 2; i)
{
_WordsList[wordLength]["" + _WordsVector[wordLength][i++]] = true;
}
To validate a word , the following lookup returns true if valid:
function Validate(key:String):Boolean
{
return _WordsList[key.length - 2][key]
}
I transferred them from a vector to objects to take advantage of the hash take lookup of the properties. Haven't looked at how much memory this all takes but it's been a useful learning exercise.
I just wasn't sure how best to randomly choose a property from one of the objects. I was thinking of validating whatever method I chose by generating 1000 000 words and analyzing the statistics of the distribution.
So I suppose my question should really first be am I better off using some other approach such as keeping the lists in vectors and doing a search each time ?
Original question
Newbie first question:
I read a thread that said that traversal order in a for.. in is determined by a hash table and appears random.
I'm looking for a good way to randomly select a property in an object. Would the first element in a for .. in traversing the properties, or perhaps the random nth element in the iteration be truly random. I'd like to ensure that there is approximately an equal probability of accessing a given property. The Objects have between approximately 100 and 20000 properties. Other approaches ?
thanks.
Looking at the scenario you described in your edited question, I'd suggest using a Vector.<String> and your map object.
You can store all your keys in the vector and map them in the object, then you can select a random numeric key in the vector and use the result as a key in the map object.
To make it clear, take a look at this simple example:
var keys:Vector.<String> = new Vector.<String>();
var map:Object = { };
function add(key:String, value:*):void
{
keys.push(key);
map[key] = value;
}
function getRandom():*
{
var randomKey = keys[int(Math.random() * keys.length)];
return map[randomKey];
}
And you can use it like this:
add("a", "x");
add("b", "y");
add("c", "z");
var radomValue:* = getRandom();
Using Object instead of String
Instead of storing the strings you can store objects that have the string inside of them,
something like:
public class Word
{
public var value:String;
public var length:int;
public function Word(value:String)
{
this.value = value;
this.length = value.length;
}
}
Use this object as value instead of the string, but you need to change your map object to be a Dictionary:
var map:Dictionary = new Dictionary();
function add(key:Word, value:*):void
{
keys.push(key);
map[key] = value;
}
This way you won't duplicate every word (but will have a little class overhead).
Working with Arrays. I create objects on a Class base, push them into an Array, I have 2 buttons: one adds a Child and pushes it into the Array, second one Shifts Array and removes the Child. Also a function on my mouse, if I click an object, I define it's Array number, remove the Child and... well, not sure if successful but "delete Array[i];" where i is target's Array number. I can see Array.length in a text field every time I do something. Second button actually does remove an object from Array, the number decreases. But deleting a specified object from the Array, as well as Array.slice(i,1), doesn't reduce the Array length. So I'm afraid it may cause overflow. It's only Array, not sure, maybe it's fine to have over a million cells in an Array? Like if I make a game with meteor shower, meteors are removed from the screen, but the Array still has their cells. And if they appear like 30-50 per sec, it's obvious I may get memory problems in 20 minutes of running it. Well it's 60k so maybe I shouldn't worry as only graphics take much memory?
Still, I could use an advice on how to shift an object in a middle of an Array. Chosen one. How do I delete it as if it never was created, same as Shift does? (it does, right?)
Array.splice() will do most of the tricks. As you remove the meteor off screen, you can splice it out of the array, do like this:
var i:int=meteorArray.indexOf(meteorToRemove);
if (i>=0) meteorArray.splice(i,1);
You should not create a new object as a good practice if you are deleting other. Try recycling, or better said 'object pools'
You should figure out the number max of elements you may use at once. create a property 'active' on each and set it to true or false instead of creating/deleting. Then you can run the update on each object and update it only if necessary
For example:
var meteors:Array = [];
// create 500 meteors
for ( var i:int = 0; i < 500; i++ ) {
var meteor:Meteor = new Meteor();
meteor.active = false;
meteors.push(meteor);
}
// enable one meteor
meteors[0].active = true;
// in your update method:
for each (var meteor in meteors )
if ( meteor.active )
meteor.update();
Hope that helps.
Also you can add a helper method to get a meteor available:
function getMeteorAvailable():Meteor
{
for each (var meteor in meteors )
if ( !meteor.active )
return meteor;
}
I'm trying to create a flash application that will keep track of user generated values. The app should basically allow the user to input the name of the item and it's cost. The total costs should then be added up to show a total value to the user. I can probably figure out how to add the values together, but I'm not really sure how to allow the user to create a list and then allow the user to save it. Can anyone point me towards a tutorial or point me in the right direction?
I am using variables to add user inputed numbers to come up with a total. The first problem is that actionscript 3.0 does not allow variables for texts. I just converted it to 2.0 to fix this. The second problem, is when I test the app and put in my values and click submit, I get NaN in the total values field. Is there a reason why it wouldn't add the values?
Here is the code I used for the submit button:
on (release) {
total = Number(rent) + Number(food) + Number(travel) + Number(entertainment) + Number(bills);
}
Am I missing anything?
Can I give the input text instance names and then give them variables? How are some ways to go about this?
Thanks for the help!
Have an object array, say for example
var stack:Array = new Array();
Then push the item name and it's cost to that array when user inputs, like
stack.push({item:AAA, cost:xx});
So that you can generate the list whenever you want with that array.
You have to see how this works in code. A list in actionscript could be stored inside an array, vector, dictionary or even an Object.
Var myList:Array = [];
myList.push({name: "item 1", cost: 5 });
myList.push({name: "item 2", cost: 7.5 });
If you want to grab the 'product' of "item 1" from the list, you have to create a function for that, lets call it getProductByName
function getProductByName(name:String):Object
{
for each(var product:Object in myList)
{
if (product.name === name) return product;
}
return null; // no match found
}
You can call that function like this:
var product = getProductByName("item 1");
trace(product.cost); // 5
And you can alter the product, so lets make it more expensive
product.cost += 1;
trace(product.cost); // 6
Have fun! If you are using classes, you would create one for the product, with public name and cost, and in that case you'de better use a vector, to ensure working with the right type.
This is what fixed the issue for me in action script 3.0:
myButton.addEventListener(MouseEvent.CLICK, addThem);
function addThem(e:MouseEvent)
{
totalField.text = String ( Number(field1.text) + Number(field2.text) + ....);
}
I also had to name the instances appropriately.
I was trying to make a similar thing with the game SameGame (ie. the block above the removed blocks fall downward). Before trying this with an Array that contains MovieClips, this code worked (tried it with int values). With MovieClips on the array, it seems not working the same way.
With int values, example:
popUp(0, 4): Before: 1,2,3,4,5,6,7,8,9,10; After: 1,2,3,4,6,7,8,9,10
But with MovieClips:
popUp(0, 4): Before: 1,2,3,4,5,6,7,8,9,10; After; 1,2,3,4
// Assume the numbers are movieclips XD
Basically, it strips everything else, rather than just the said block >_<
Here's the whole method. Basically, two extra arrays juggle the values above the soon-to-be removed value, remove the value, then re-stack it to the original array.
What could be wrong with this? And am I doing the right thing for what I really wanted to emulate?
function popUp(col:uint, row:uint)
{
var tempStack:Array = new Array();
var extraStack:Array = new Array();
tempStack = IndexArray[col];
removeChild(tempStack[0]);
for(var ctr:uint = tempStack.length-(row+1); ctr > 0; ctr--)
{
removeChild(tempStack[ctr]);
extraStack.push(tempStack.pop());
trace(extraStack);
}
tempStack.pop();
for(ctr = extraStack.length; ctr > 0; ctr--)
{
tempStack.push(extraStack.pop());
//addChild(tempStack[ctr]);
}
IndexArray[col] = tempStack;
}
PS: If it's not too much to ask, are there free step-by-step guides on making a SameGame in AS3 (I fear I might not be doing things right)? Thanks in advance =)
I think you just want to remove an element and have everything after that index shift down a place to fill what you removed. There's an inbuilt function for this called splice(start:uint, length:uint);
Parameters:
start - the index to start removing elements from
length - the amount of elements to remove
var ar:Array = ["hello","there","sir"];
ar.splice(1, 1);
ar is now -> ["hello", "sir"];
As per question:
Here's an example with different types of elements:
var ar:Array = [new MovieClip(), "some string", new Sprite(), 8];
ar.splice(2, 1);
trace(ar); // [object MovieClip], some string, 8
And further example to display the indexes being changed:
trace(ar[2]); // was [object Sprite], is now 8