AS3 - Fast search through array with strings - arrays

Question

I need help. I am making something like dictionary (but you are filling it by yourself). I need fast search for words in it. I need to use Object or Array (because Dictionary is not supported by JSON. There is option to save file). I have this code, but I am afraid it is not so optimized to search fast when there will be a lot of words in array. Please help.
public function Search (string:String,section:String = Wordbook.NEWW):int
{
var str:String = string.toUpperCase();
for (i = 0; i < NewWords.length; i++)
{
if (NewWords[i].toUpperCase.indexOf(str) > -1)
{
return i;
}
}
return -1;//If not found
}
And example how it should work: (SearchTxt - text field, user should type here word he need to find; WB - Wordbook class; WB.NewWords & WB.NewWordsT - Arrays in this class)
var index:int = WB.Search(SearchTxt.text,Wordbook.NEWW);
if(index>-1){
WordTxt.text = WB.NewWords[index];
TranslationTxt.text = WB.NewWordsT[index];
} else {
dispatchEvent(new EventWithMessage(EventWithMessage.ERROR,{error:"No match!"}));
}

Answer 1

There are two solutions here, depending on your use-cases.
Solution 1: Leave it alone!
If the biggest dictionary you're going to build is only a hundred words or so, performance will be fine with a linear search.
Solution 2: Implement a binary search algorithm
If you do need to deal with large dictionaries of thousands of words, a binary search algorithm will offer improved performance. For this, you'll need to guarantee that your search array is sorted.
Something like this should do the trick:
public function Search (string:String,section:Array = NewWords, offset:int = 0):int
{
if (section.length == 0) {
return -1;
}
var str:String = string.toUpperCase();
var firstCharCode:int = str.charCodeAt(0);
var middleWord:String = section[section.length / 2];
var middleWordCharCode:int = middleWord.charCodeAt(0);
if (middleWord.substr(0,str.length) == str) {
return (section.length / 2) + offset;
} else {
var comparison:int = str.localeCompare(middleWord);
if (comparison < 0) {
return Search(string, section.splice(0, section.length / 2), offset);
} else { // then comparison > 0
var newOffset:int = offset + section.length / 2;
return Search(string, section.splice(section.length / 2, section.length-1), newOffset);
}
}
}