finding sequences in AS3 array

问题

does anyone have any idea what to do in order to find the number of sequences in an array?

for example, my array is:

var numbers:Array = new Array(banana, banana, apple, banana, banana);

and i need to find is: * how many times there is a sequence of "banana" * and the length of each sequence.

what shell i do in order to get the following result: 2,1,2 (2 bananas, 1 apple, 2 bananas)

i tried with do while loop, but i i guess i miss something.

a short example will be very appreciated!

thanx

回答1:

var prev:String = null;
var q:int = 0;
var result:Array = new Array();
for(var i:int=0; i<numbers.length; ++i){
  if(prev!=numbers[i]){
    if(q>0) result.push(q);
    q=1;
    prev=numbers[i];
  }
  else ++q;
}
if(q>0) result.push(q);

This is, assuming banana, etc. are strings (probably a typo above?). It would be simple to modify to other types of objects

回答2:

Really all you want to know is whether the string at index n equals the string at index n+1...

var targetIndex:int = numbers.length - 1;
var results:Array = [1];
var resultsIndex:int = 0;
for(var n:int = 0; n < targetIndex; n++) {
    if(numbers[n] == numbers[n+1]) {
        results[resultsIndex]++;
    } else {
        results[++resultsIndex] = 1;
    }
}
trace(results.join(','));

回答3:

function sequencesInArray(array:Array):Array {
    var sequence:Array = [];
    var currSequenceCount:uint = 1;
    for (var i:uint = 1; i < numbers.length; i++) {
        if (numbers[i - 1] != numbers[i]) {
            sequence.push(currSequenceCount);
            currSequenceCount = 1;
        } else {
            currSequenceCount++;
        }
    }
    return sequence;
}

Then:

var banana:int = 1;
var apple:int = 2;
sequencesInArray([banana, banana, apple, banana, banana]); //returns: [2, 1, 2]

回答4:

In the question you don't define banana and apple, anyway I would use a map or a Dictionary to store key/value pairs, with the key being the string/object you want to count and the value being the counter of the object occurences in your array.

var objectsCounter:Dictionary = new Dictionary();

for (var key:String in numbers) 
{
    if ( objectsCounter[key] )
        objectsCounter[key] = objectsCounter[key] + 1;
    else 
        objectsCounter[key] = 1;
}

This way you can store any type in the dictionary.

edit:

for (var key:String in objectsCounter) 
{
    // iterates through each object key
}

for each (var value:Number in objectsCounter) 
{
    // iterates through each value
}

回答5:

I believe this is what you're looking for:

    var array:Array = [
        "banana", "banana",
        "apple",
        "banana", "banana", "banana"
    ];

    var sequences:Array = findSequences(array, "banana");

    trace("sequences:", sequences); // prints "sequences: 2,3"

And:

private function findSequences(array:Array, searchElement:*):Array
{
    var sequences:Array = [];
    var currentSequence:int = 0;

    for each (var element:* in array) {
        if (element == searchElement) {
            currentSequence++;

        } else if (currentSequence > 0) {
            sequences.push(currentSequence);
            currentSequence = 0;
        }
    }

    if (currentSequence > 0) {
        sequences.push(currentSequence);
    }

    return sequences;
}

来源：https://stackoverflow.com/questions/9485615/finding-sequences-in-as3-array