Web студия "GrandView"

add a note User Contributed Notes
is_bool

admin @ ifyouwantblood DOTTY de
19-Oct-2007 06:04


@ emmanuel del grande and kevin at metalaxe dot com



also there is settype: http://us.php.net/settype

bb at kingdom dot cjb dot net
27-Jun-2007 02:57


@ emmanuel del grande



You don't need to break when you return...



function bool($var) {

    switch (strtolower($var)) {

        case ("true"): return true;

        case ("false"): return false;

        default: die("whatever you want it to tell");

    }

}

kevin at metalaxe dot com
05-Jun-2007 01:32


@ emanueledelgrande at email dot it



http://us.php.net/manual/en/language.types.type-juggling.php



(bool) or (boolean) is allowed for type casting a variable. No function like intval, etc but the functionality exists.

emanueledelgrande at email dot it
22-May-2007 09:12


I think there's a hole in the PHP typecasting methods:

you have the (int) function, the (float) function and the (string) function, but no function to force a string variable into the boolean type.



It's obvious that forcing unconditionally the type of variables into arrays and objects is inappropriate, but boolean type is the most basic one for each programming language, that's why I guessed that a (bool) function already existed.



Moreover, with the increasing trend of RSS data streaming, the parsing of an XML string into an object often requires to typecast as boolean values the content of XML tags, normally returned as string by the object method get_content().



I wrote the following function, which also uses a "native PHP style" error message:



<?php

// strings tyecasting as boolean values:

function bool($var) {

    switch (strtolower($var)) {

        case ("true"):

            return true;

            break;

        case ("false"):

            return false;

            break;

        default:

            die("<br />\n<b>Warning:</b> Invalid argument supplied for ".__FUNCTION__." function in <b>".__FILE__."</b> on line <b>".__LINE__."</b>: the argument can contain only 'true' or 'false' values as a string.<br />\n");

    }

}

?>



Here it is a small example:



<?php

$xmlResponse = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";

$xmlResponse .= "<Result>";

$xmlResponse .= "<AuthError>false</AuthError>";

$xmlResponse .= "<TransferStatus>true</TransferStatus>";

$xmlResponse .= "</Result>";



if (! $responseDoc = domxml_open_mem($xmlResponse, DOMXML_LOAD_PARSING, $XmlParsingError)) {

    echo "Error while parsing the XML string:<br />".print_r($XmlParsingError, TRUE);

} else {

    $ResultNode = $responseDoc->get_elements_by_tagname('Result');

    

    $AuthError = $ResultNode[0]->get_elements_by_tagname('AuthError');

    $auth_error = bool($AuthError[0]->get_content());

    

    $TransferStatus = $ResultNode[0]->get_elements_by_tagname('TransferStatus');

    $transfer_status = bool($TransferStatus[0]->get_content());

    

    if (! $auth_error) { echo "Auth OK<br />"; } else { echo "Auth error<br />"; }

    if ($transfer_status) { echo "Transfer OK<br />"; } else { echo "Transfer error<br />"; }

}



?>



It would be useful this function to be implemented in the core of PHP5.

21-Apr-2006 04:12


Small caveat to rh's post: back in PHP 3, "0" would be considered non-empty (i.e., empty would return false), even though (bool) on "0" would also evaluate to false; thus, they would not be complete opposites for someone using PHP 3.

rh at richardhoward dot net
22-May-2005 11:17


punkpuke is wrong here; what he means to say is that empty($x) is the opposite of (bool)$x.  is_bool($x) returns true where $x === false.

add a note

is_bool

Описание

Список параметров

Возвращаемые значения

Примеры

Смотрите также