AS3 Basics: String Manipulation in Actionscript 3.0

I’ve been developing apps in Flash Actionscript 2.0 (AS2) for about a 1/2 years now. But the other day i finally bit the bullet and decided to start learning Actionscript 3.0 (AS3). AS3 is the next big step in flash application development boasting a complete re-write with faster excecution speed, fully re-vamped event hadling system and classes work a hell of a lot like they’re supposed to (thank you Adobe!). Basicaly AS3 is pretty awesome.
In this set of tutorials i will be going over the basics of AS3, As a reminder to myself and to maybe help some people along the way. However be aware i’m not perfect and if you’re a seasoned programmer please point out my oddities

(Please Note i expect a basic understanding of programming syntax and variable types)

place this code on frame 1 of you’re time line.

var myString:String = "Hello this is my string! BEANS!";
function main():void
{
trace("--Main function ran--");
trace(myString);
}
main();

If you run you’re file now it should output “Hello this is my string! BEANS!”.

Code Explanation (skip if you already know you 1337 pr0gr4mm3r2):

var myString:String = "hello this is my string! BEANS!";

This line defines our string we are going to be manipulating. Notice ‘:String’ after the variable name. This is strict programming so that my variable ‘myString’ can not be populated with another variable type such as “int” or “Number”.

function main():void

defines our main function, Any statement within the braces {} will be excecuted upon calling the function.

trace("--Main function ran--");

trace(myString);

basic ‘trace();’ function displays text to flash’s output box. You can trace pretty much any type of data (very good for debugging).

main();

this last line calls our ‘main’ function and excecutes the statements within it.

Now on to the text manipulation…

Finding the length of characters in a string:

myString.length;

very simple, gets the length of the target string (all characters including spaces) much like an array starting from ’0′.

NOTE: length is an “int” variable, thus it cannot be displayed in a text field, use ‘toString();’ to convert it to a string.

trace(myString.length.toString());

Finding a single character in a string using and index number:

myString.charAt(0);

This function will return a single character based on the index given just like an array index.

EXAMPLE
so if i were to use,

trace(myString.charAt(9));

the output would be ‘s’.

Changing the case of a string:

myString = myString.toLowerCase();

myString = myString.toUpperCase();

These two functions will change the case of the entire string given.

Extracting a selection from a string:

myString.substring(0,5);

Will extract from char ’0′ to char ’5′.

EXAMPLE

trace(myString.substring(0,5));

would output “Hello”.

NOTE: you instead of “substring(0,5)” you can use a shorthand of “substr(0,5)”.

NOTE: You can also use the ‘slice();’ function to do the same thing however it is better used with arrays.

Replacing characters in a string with another string:

myString.replace(0,"WEE");

replaces the targeted range of existing characters with the chosen string "WEE".

EXAMPLE
using in combination with ‘myString.substring(0,5)’ to find the range to replace.

trace(myString.replace(myString.substring(0,5),"WOO"));

the above would output “WOO this is my string! BEANS!”.

Well thats all the methods i know of at this time i’ve compiled them all into a .FLA  demonstrating the usage of each.