Validators

Alpha

Zend\I18n\Validator\Alpha allows you to validate if a given value contains only alphabetical characters. There is no length limitation for the input you want to validate. This validator is identical to the Zend\I18n\Validator\Alnum validator with the exception that it does not accept digits.

Basic Usage

$validator = new Zend\I18n\Validator\Alpha();

if ($validator->isValid('Abcd')) {
    // value contains only allowed chars
} else {
    // false
}

Using Whitespace

By default, whitespace is not accepted as it is not part of the alphabet. However, if you want to validate complete sentences or phrases, you may need to allow whitespace; this can be done via the allowWhiteSpace option, either at instantiation or afterwards via the setAllowWhiteSpace() method.

$validator = new Zend\I18n\Validator\Alpha(['allowWhiteSpace' => true]);

if ($validator->isValid('Abcd and efg')) {
    // value contains only allowed chars
} else {
    // false
}

$validator = new Zend\I18n\Validator\Alpha();
$validator->setAllowWhiteSpace(true);

if ($validator->isValid('Abcd and efg')) {
    // value contains only allowed chars
} else {
    // false
}

Get Current Value

To get the current value of this option, use the getAllowWhiteSpace() method.

$validator = new Zend\I18n\Validator\Alpha(['allowWhiteSpace' => true]);

var_dump($validator->getAllowWhiteSpace()); // true

Default Value

The default value of this option is false that means whitespace characters are not allowed.

Using different Languages

When using Zend\I18n\Validator\Alpha, the language provided by the user's browser will be used to set the allowed characters. For locales outside of English, this means that additional alphabetic characters may be used — such as ä, ö and ü from the German alphabet.

Which characters are allowed depends completely on the language, as every language defines its own set of characters.

Three languages supported by PHP's internationalization extension (ext/intl), however, define multibyte characters, which cannot be matched as alphabetic characters using normal string or regular expression options. These include Korean, Japanese, and Chinese.

As a result, when using the Alpha validator with these languages, the input will be validated using the English alphabet.