AS3: Large text files with indexOf() on an array
package {
    import flash.display.MovieClip;

    public class DictionaryCheck extends MovieClip {

        [Embed(source="test.txt",mimeType="application/octet-stream")] // Works fine 10 rows.
                //[Embed(source="sowpods.txt",mimeType="application/octet-stream")] //Won't work too large.
        private static const DictionaryFile:Class;

        private static var words:Array = new DictionaryFile().toString().split("n");

        public function DictionaryCheck() {
            containsWord("AARDVARKS");
        }

        public static function containsWord(word:String):* {
            trace(words[10]); //Traces "AARDVARKS" in both versions of file
            trace((words[10]) == word); // Traces true in shorter text file false in longer
            trace("Returning: " + (words.indexOf(word))); // traces Returning: 10 in smaller file
            if((words.indexOf(word)) > -1){
               trace("Yes!"); // traces "Yes" in shorter file not in longer
            }
        }
    }
}

private static var dicts:Object;

public function createDicts() {
    var first_letter:String;
    for (i = 0; i < words.length; i++) {
        first_letter = words[i].charAt(0);
        if (dicts[first_letter] == undefined) {
            dicts[first_letter] = {}
        }
        dicts[first_letter][words[i]] = 'X';
    }
}

public static function containsWord(word:String):Boolean {
    first_letter = words[i].charAt(0);
    if (dicts[first_letter]) {
        return dicts[first_letter][word] != undefined;
    }
    return false;
}

public class DictSOWPODS {
    protected var parsedDictionary : Array = ["firstword", "secondword", ..., "lastword"]; // yes, this will be the hugest array initialization you've ever seen, just make sure it's sorted so you can search it fast

    public function containsWord(word : String) : Boolean {
        var result : Boolean = false;
        // perform the actual half-interval search here (please do not keep it this way)
        var indexFound : int = parsedDictionary.indexOf(word);
        result = (indexFound >= 0)
        // end of perform the actual half-interval search (please do not keep it this way)
        return result;
    }
}