Search and Replace in Flash/Flex

ActionScript 3 is one of the few languages I’ve ever worked with that lacks a native search and replace string function. In earlier versions of ActionScript it was necessary to hand-write a function to achieve this but AS3 can do it, just not as easily as it should.

Not surprisingly, it’s a method of the string class called “replace”. If I wanted to find the first occurence of “abc” in a string called myString, and replace it with “xyz” I could do it like this:

var str:String = “This string has abc in it.”;
str.replace(“abc”, “xyz”);

Which is all well and fine except that, in nearly all cases when I use replace, I want to replace all occurences, not just the first one. To do this is a little more complicated and involves creating a Regular Expression object like this:

var myRegExp:RegExp=new RegExp(“abc”,”g”);
var str:String = “This string has abc abc abc in it.”;
str.replace(myRegExp, “xyz”);

This is hardly using Regular Expressions at all but it is making use of the “g” flag which tells the replace method to replace all occurences (it stands for “global”).