# Regex

This validator allows you to validate if a given string conforms a defined regular expression.

## Supported options for Zend_Validate_Regex

The following options are supported for `Zend_Validate_Regex`:

- pattern: Sets the regular expression pattern for this validator.

## Validation with Zend_Validate_Regex

Validation with regular expressions allows to have complicated validations being done without writing a own validator. The usage of regular expression is quite common and simple. Let's look at some examples:

    $validator = new Zend_Validate_Regex(array('pattern' => '/^Test/');

    $validator->isValid("Test"); // returns true
    $validator->isValid("Testing"); // returns true
    $validator->isValid("Pest"); // returns false

As you can see, the pattern has to be given using the same syntax as for `preg_match()`. For details about regular expressions take a look into PHP's manual about PCRE pattern syntax.

## Pattern handling

It is also possible to set a different pattern afterwards by using `setPattern()` and to get the actual set pattern with `getPattern()`.

    $validator = new Zend_Validate_Regex(array('pattern' => '/^Test/');
    $validator->setPattern('ing$/');

    $validator->isValid("Test"); // returns false
    $validator->isValid("Testing"); // returns true
    $validator->isValid("Pest"); // returns false