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SirGordon/random.as

Last active August 29, 2015 14:26
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random.as
public static function generateRandomResultBasedOnWeights(weights:Array):int {
weights.sort(Array.DESCENDING);
var sum:Number = sumArrayElements(weights);
var r:Number = Math.random() * sum;
var result:int = -1;
for (var i:uint = 0; i < weights.length; i++) {
var item:int = weights[i];
if (r < item)
return result;
r -= item;
}
return result;
}
Raw
random.js
function generateRandomResultBasedOnWeights(weights) {
//weights.sort(sortFunction);
var sum = sumArrayElements(weights);
console.log("sum: " + sum);
var r = Math.random() * sum;
var result = {value: "nothing"};
for (var i = 0; i < weights.length; i++) {
var item = weights[i];
if (r < item.weight)
return item;
r -= item.weight;
}
return result;
}
function sumArrayElements(array){
var result = 0;
for(var i = 0; i<array.length; i++){
result += array[i].weight;
}
return result;
}
function sortFunction(a, b) {
return b.weight - a.weight;
}
function main(){
var arr = [
{value:"gold", weight:70},
{value:"potion", weight:20},
{value:"shit", weight:10}
];
arr = arr.sort(sortFunction);
var results = {
gold: 0,
potion: 0,
shit: 0,
nothing: 0
};
for(var i=0; i<10000; i++){
var result = generateRandomResultBasedOnWeights(arr);
results[result.value]++;
}
alert("gold " + results.gold + "\npotion " + results.potion + "\nshit " + results.shit + "\nnothing " + results.nothing);
//output: gold ~7000, potion ~2000, shit ~1000
}
main();
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