Question

我想计算ActionScript 3.0中数组中出现的次数。说我有

var item:Array = ["apples", "oranges", "grapes", "oranges", "apples", "grapes"];

如何让它显示匹配字符串的数量？例如，结果：apples = 2，oranges = 2等。

我从另一个类似的问题中得到了这段代码：

    private function getCount(fruitArray:Array, fruitName:String):int {
    var count:int=0;
    for (var i:int=0; i<fruitArray.length; i++) {
        if(fruitArray[i].toLowerCase()==fruitName.toLowerCase()) {
            count++;
        }
    }
    return count;
}

var fruit:Array = ["apples", "oranges", "grapes", "oranges", "apples", "grapes"];
var appleCount=getCount(fruit, "apples"); //returns 2
var grapeCount=getCount(fruit, "grapes"); //returns 2
var orangeCount=getCount(fruit, "oranges"); //returns 2

在这段代码中，如果你想获得说“苹果”的数量。您需要为每个项目设置变量（var appleCount = getCount（fruit，“apples”））。但是，如果你有成百上千的水果名称，就不可能为每一个水果写下新的变量。

我是AS3的新手，请原谅我。请在代码中包含明确的注释，因为我想了解代码。

Answer 1

    var item:Array = ["apples", "oranges", "grapes", "oranges", "apples", "grapes"];

    //write the count number of occurrences of each string into the map {fruitName:count}
    var fruit:String;
    var map:Object = {}; //create the empty object, that will hold the values of counters for each fruit, for example map["apples"] will holds the counter for "apples"

    //iterate for each string in the array, and increase occurrence counter for this string by 1 
    for each(fruit in item)
    {
        //first encounter of fruit name, assign counter to 1
        if(!map[fruit])
            map[fruit] = 1;
        //next encounter of fruit name, just increment the counter by 1
        else
            map[fruit]++;
    }

    //iterate by the map properties to trace the results 
    for(fruit in map)
    {
        trace(fruit, "=", map[fruit]);
    }

输出：

apples = 2
grapes = 2
oranges = 2

计算数组中出现的次数

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