ActionScript for Flash MX: The Definitive Guide, Second Edition

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Chapter 4: Primitive Datatypes

Notice how the logical OR operator (||) lets us check two conditions at once. We’ll

study OR in Chapter 5.

You may encounter the deprecated

gt, ge, lt, and le operators, used for string com-

parison in Flash 4, when examining legacy code. The

>, >=, <, and <= operators

should be used in Flash 5 and later.

Using Built-in String Functions

With the exception of the concat() function, every tool we’ve used with strings so far

has been an operator. Now we’ll see how to use built-in functions and properties to

perform more advanced string manipulation.

To execute a built-in function on a string, we must perform a function call, which

takes the form:

string.functionName(arguments)

For example, here we execute the charAt() function on myString:

myString.charAt(2)

Many string functions return a new string derived from the original string. We assign

these return values to variables or object properties for future use, such as:

thirdCharacter = myString.charAt(2);

Character Indexing

Many of the string functions make use of a character’s index—its numeric position

relative to the string’s first character, starting at 0, not 1. The first character is num-

bered 0, the second is numbered 1, the third is numbered 2, and so on. For example,

in the string “red”, the r is at ...