Question

I have an Array of Objects which I want to filter depending on some search Strings. I want to create a new array from my original array which will only contain Objects which have properties equal to the Strings in the search:

    var _array =  new Array();
    _array.push({name:"Ben",Title:"Mr",location:"UK"});
    _array.push({name:"Brian",Title:"Mr",location:"USA"});
    _array.push({name:"Ben",Title:"Mr",location:"USA"});

    var searchQuery:Array = new Array();
    searchQuery.push("Ben");
    searchQuery.push("Mr");

I want the new Array to contain the first and the last Object as they both contain the Strings “Ben” and “Mr”.

Can I use the Array.filter to achieve this?

Any help appreciated.

Answer 1

Ah nothing quite like a good old collections problem 🙂

Although JiminP’s answer is indeed correct; it suffers from a couple of performance concerns; the biggest of which being that closures in AS3 are slow, so if you are searching over a large Array the operation could run slowly.

The following function isn’t quite as clean, but will yeild better performance over a large Array.

var _array : Array = [];
_array.push({name:"Ben", Title:"Mr", location:"UK"});
_array.push({name:"Brian", Title:"Mr", location:"USA"});
_array.push({name:"Ben", Title:"Mr", location:"USA"});

// I presumed you would want a little bit more control over the search matching; by
// using a Map you can ensure that no-one with the (somewhat unlikley) name of "Mr"
// gets matched by mistake.
var searchQueryMap : Dictionary = new Dictionary();
searchQueryMap["name"] = "Ben";
searchQueryMap["Title"] = "Mr";

const results : Array = [];

// Loop over earch objectin the 'haystack' that we wish to search.
for each (var object : Object in _array) 
{
    // This variable is used to break out of the loop if the current object doesn't match the
    // searchQueryMap; this gets reset to true for each loop of the supplied array.
    var match : Boolean = true;

    // Loop over each key (property) in the searchQueryMap.
    for (var key : * in searchQueryMap) 
    {
        if (searchQueryMap[key] !== object[key]) 
        {
            // No match, we can break out of looping over the searchQueryMap here.
            match = false;
            break;          
        }
    }

    // Check to see if we still have a positive match; if we do, push it onto the results Array.
    if (match) {
        results.push(object);   
    }
}

// Debug the results.
trace("Matches:");
for each (var result : Object in results)
{
    for (var prop : * in result) {
        trace("\t" + prop + " => " + result[prop]);
    }
    trace("---");
}