WC_Validation::is_gb_postcode() │ public static │ WC 1.0

Check if is a GB postcode.

Method of the class: WC_Validation{}

No Hooks.

Return

true|false.

Usage

$result = WC_Validation::is_gb_postcode( $to_check );

$to_check(string) (required)

A postcode.

WC_Validation::is_gb_postcode() WC Validation::is gb postcode code ^{WC 9.4.2}

public static function is_gb_postcode( $to_check ) {

	// Permitted letters depend upon their position in the postcode.
	// https://en.wikipedia.org/wiki/Postcodes_in_the_United_Kingdom#Validation.
	$alpha1 = '[abcdefghijklmnoprstuwyz]'; // Character 1.
	$alpha2 = '[abcdefghklmnopqrstuvwxy]'; // Character 2.
	$alpha3 = '[abcdefghjkpstuw]';         // Character 3 == ABCDEFGHJKPSTUW.
	$alpha4 = '[abehmnprvwxy]';            // Character 4 == ABEHMNPRVWXY.
	$alpha5 = '[abdefghjlnpqrstuwxyz]';    // Character 5 != CIKMOV.

	$pcexp = array();

	// Expression for postcodes: AN NAA, ANN NAA, AAN NAA, and AANN NAA.
	$pcexp[0] = '/^(' . $alpha1 . '{1}' . $alpha2 . '{0,1}[0-9]{1,2})([0-9]{1}' . $alpha5 . '{2})$/';

	// Expression for postcodes: ANA NAA.
	$pcexp[1] = '/^(' . $alpha1 . '{1}[0-9]{1}' . $alpha3 . '{1})([0-9]{1}' . $alpha5 . '{2})$/';

	// Expression for postcodes: AANA NAA.
	$pcexp[2] = '/^(' . $alpha1 . '{1}' . $alpha2 . '[0-9]{1}' . $alpha4 . ')([0-9]{1}' . $alpha5 . '{2})$/';

	// Exception for the special postcode GIR 0AA.
	$pcexp[3] = '/^(gir)(0aa)$/';

	// Standard BFPO numbers.
	$pcexp[4] = '/^(bfpo)([0-9]{1,4})$/';

	// c/o BFPO numbers.
	$pcexp[5] = '/^(bfpo)(c\/o[0-9]{1,3})$/';

	// Load up the string to check, converting into lowercase and removing spaces.
	$postcode = strtolower( $to_check );
	$postcode = str_replace( ' ', '', $postcode );

	// Assume we are not going to find a valid postcode.
	$valid = false;

	// Check the string against the six types of postcodes.
	foreach ( $pcexp as $regexp ) {
		if ( preg_match( $regexp, $postcode, $matches ) ) {
			// Remember that we have found that the code is valid and break from loop.
			$valid = true;
			break;
		}
	}

	return $valid;
}