String Class

	ActionScript for Flash MX: The Definitive Guide, 2nd Edition By Colin Moock

	Chapter 18. ActionScript Language Reference

String Class

Flash 6

wrapper class for string primitive typeFlash 5; performance enhanced in

Constructor

new String(value)

Arguments

value: An expression to be resolved and, if necessary, converted to a string, then wrapped in a String object.

Properties

length: The number of characters in a string.

Class Methods

The following method is invoked through the String class itself, not through an object of the String class:

fromCharCode( ): Generate a string from one or more Unicode code points.

Methods

The following object methods are invoked through an instance of the String class:

charAt( ): Retrieve a character at a specific position in the string.
charCodeAt( ): Retrieve the code point of a character at a specific position in the string.
concat( ): Combine one or more items into a single string.
indexOf( ): Find the first occurrence of a specified substring in a string.
lastIndexOf( ): Find the last occurrence of a specified substring in a string.
slice( ): Extract a substring from a string, based on positive or negative character positions.
split( ): Convert a string to an array.
substr( ): Extract a substring from a string, based on a starting position and length.
substring( ): Extract a substring from a string, based on positive character positions only.
toLowerCase( ): Return a lowercase version of a string.
toUpperCase( ): Return an uppercase version of a string.

Description

The String class has several purposes:

It allows us to access the length property of strings and perform string-related operations, such as indexOf( ) and slice( ). String objects are created (and eventually deleted) automatically by the interpreter whenever a method is invoked on a primitive string value.
It can be used to convert a datum of any type to a string.
It is used to access the fromCharCode( ) class method to create a new string, based on specified Unicode code points.
It can be used to create a String object, which contains a primitive string value in an unnamed, internal property; however, there is little reason to do so.

In Flash 6, the performance (speed) of the String class methods is vastly improved over Flash 5 performance. Flash Player 6 executes most String methods 50 to 1000 times faster than Flash Player 5.

Usage

In practice, the String class constructor is used primarily to convert other datatypes to strings. See the String( ) global function for more details.