is_binary
@ 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");
}
}
is_bool
(PHP 4, PHP 5)
is_bool — Détermine si une variable est un booléen
Liste de paramètres
- var
-
La variable à évaluer.
Valeurs de retour
Retourne TRUE si var est un booléen, FALSE sinon.
Exemples
Exemple #1 Exemple avec is_bool()
<?php
$a = false;
$b = 0;
// Si $a est un booléen, ceci sera vrai
if (is_bool($a)) {
echo "Oui, c'est un booléen.";
}
// Si $b n'est pas un booléen, ceci sera faux
if (is_bool($b)) {
echo "Oui, c'est un booléen.";
}
?>
add a note
User Contributed Notesis_bool
bb at kingdom dot cjb dot net
27-Jun-2007 11:57
27-Jun-2007 11:57
kevin at metalaxe dot com
05-Jun-2007 10:32
05-Jun-2007 10:32
@ 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 06:12
22-May-2007 06:12
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 01:12
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 08:17
22-May-2005 08:17
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.