Developer Guide
Methods for using regular expressions with strings
The RegExp class includes two methods: exec() and test().
In addition to the
exec() and test() methods of the RegExp class, the String class includes the following methods
that let you match regular expressions in strings:
match(), replace(), search(), and splice().
The test() method
The test() method of the RegExp class simply checks the supplied string to see if it contains a match for the regular
expression, as the following example shows:
var pattern:RegExp = /Class-\w/;
var str = "Class-A";
trace(pattern.test(str)); // output: true
The exec() method
The exec() method of the RegExp class checks the supplied string for a match of the regular expression and returns
an array with the following:
The matching substring
Substring matches for any parenthetical groups in the regular expression
The array also includes an
index property, indicating the index position of the start of the substring match.
For example, consider the following code:
var pattern:RegExp = /\d{3}\-\d{3}-\d{4}/; //U.S phone number
var str:String = "phone: 415-555-1212";
var result:Array = pattern.exec(str);
trace(result.index, " - ", result);
// 7-415-555-1212
Use the exec() method multiple times to match multiple substrings when the g (global) flag is set for the regular
var pattern:RegExp = /\w*sh\w*/gi;
var str:String = "She sells seashells by the seashore";
var result:Array = pattern.exec(str);
while (result != null)
trace(result.index, "\t", pattern.lastIndex, "\t", result);
result = pattern.exec(str);
// 0 3 She
// 10 19 seashells
// 27 35 seashore
String methods that use RegExp parameters
The following methods of the String class take regular expressions as parameters: match(), replace(), search(),
split(). For more information on these methods, see “Finding patterns in strings and replacing substrings” on
page 136.

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