Change A Character In A String Using Actionscript

Question

What is the opposite of String.charAt()??

If I Have a string:

var Str:String=\"Hello World\";

How do I change the 5th chara

Answer 1

That answer was such a big help, but i think theres an easyer way. Suppose you want to replace the 4th character of a string called B by the letter "w". You can use

B = B.replace(B.charAt(4), "w");

Im using flash cs4 with actionscript 3.0, if it doesnt works with someone, let me know. If theres a evenbetter way of doing it let me know aswell.