is_binary
Seems this is a most wanted function, so here is my version of it. I have been using this one for several years no and it works perfect for my needs. I have added "sloppy" human logic to it, and you could easily extend to your flavour. Like in norway some would use "ja" and "nei" instead of "yes" and "no".
<?php
/**
* Checks a variable if it is true or false, humanlike.
* We account for values as 'on', '1', '' and so on.
* Finally, for some reare occurencies we account with
* crazy logic to fit some arrays and objects.
*
* @author Kim Steinhaug, <kim@steinhaug.com>
* @param mixed $var, the variable to check
*
* Example:
* $test = 'true';
* if(_bool($test)){ echo 'true'; } else { echo 'false'; }
*/
function _bool($var){
if(is_bool($var)){
return $var;
} else if($var === NULL || $var === 'NULL' || $var === 'null'){
return false;
} else if(is_string($var)){
$var = trim($var);
if($var=='false'){ return false;
} else if($var=='true'){ return true;
} else if($var=='no'){ return false;
} else if($var=='yes'){ return true;
} else if($var=='off'){ return false;
} else if($var=='on'){ return true;
} else if($var==''){ return false;
} else if(ctype_digit($var)){
if((int) $var)
return true;
else
return false;
} else { return true; }
} else if(ctype_digit((string) $var)){
if((int) $var)
return true;
else
return false;
} else if(is_array($var)){
if(count($var))
return true;
else
return false;
} else if(is_object($var)){
return true;// No reason to (bool) an object, we assume OK for crazy logic
} else {
return true;// Whatever came though must be something, OK for crazy logic
}
}
?>
is_bool
(PHP 4, PHP 5)
is_bool — 변수가 논리형인지 확인
인수
- var
-
평가할 변수.
반환값
var 가 boolean이면 TRUE, 아니면 FALSE를 반환합니다.
예제
Example #1 is_bool() 예제
<?php
$a = false;
$b = 0;
// $a는 논리형이기 때문에, true입니다.
if (is_bool($a)) {
echo "논리형입니다.";
}
// $b는 논리형이 아니기 때문에, true가 아닙니다.
if (is_bool($b)) {
echo "논리형입니다.";
}
?>
참고
- is_float() - 변수의 자료형이 소수인지 확인합니다
- is_int() - 변수의 자료형이 정수인지 확인합니다
- is_string() - 변수의 자료형이 문자열인지 확인합니다
- is_object() - 변수가 객체인지 확인합니다
- is_array() - 변수가 배열인지 확인
add a note
User Contributed Notesis_bool
kim at steinhaug dot com
27-Aug-2009 02:48
27-Aug-2009 02:48
moty66 at gmail dot com
21-Aug-2009 06:18
21-Aug-2009 06:18
Here is the function which I use when pasring boolean variables from config files
<?php
function boolVal($var) {
switch ($var) {
case $var == true:
case $var == 1:
// case $var == '1': // no need for this, because we used
// $val == 1 not $var === 1
case strtolower($var) == 'true':
case strtolower($var) == 'on':
case strtolower($var) == 'yes':
case strtolower($var) == 'y':
$out = 1;
break;
default: $out = 0;
}
return $out;
}
?>
I am woundering why php does not have a function to do this
Motaz Abuthiab
sam+nospam at samuellevy dot com
02-Feb-2009 09:30
02-Feb-2009 09:30
Just another little function which doesn't exist yet, but I find mighty useful, especially when working with AJAX and APIs.
<?php
/** Checks a variable to see if it should be considered a boolean true or false.
* Also takes into account some text-based representations of true of false,
* such as 'false','N','yes','on','off', etc.
* @author Samuel Levy <sam+nospam@samuellevy.com>
* @param mixed $in The variable to check
* @param bool $strict If set to false, consider everything that is not false to
* be true.
* @return bool The boolean equivalent or null
*/
function boolval($in, $strict=false) {
$out = null;
// if not strict, we only have to check if something is false
if (in_array($in,array('false', 'False', 'FALSE', 'no', 'No', 'n', 'N', '0', 'off',
'Off', 'OFF', false, 0, null), true)) {
$out = false;
} else if ($strict) {
// if strict, check the equivalent true values
if (in_array($in,array('true', 'True', 'TRUE', 'yes', 'Yes', 'y', 'Y', '1',
'on', 'On', 'ON', true, 1), true)) {
$out = true;
}
} else {
// not strict? let the regular php bool check figure it out (will
// largely default to true)
$out = ($in?true:false);
}
return $out;
}
?>
It may be pretty inefficient, but it does the job.
bb at kingdom dot cjb dot net
27-Jun-2007 06:57
27-Jun-2007 06:57
@ emmanuel del grande
You don't need to break when you return...
function bool($var) {
switch (strtolower($var)) {
case ("true"): return true;
case ("false"): return false;
default: die("whatever you want it to tell");
}
}
kevin at metalaxe dot com
05-Jun-2007 05:32
05-Jun-2007 05:32
@ emanueledelgrande at email dot it
http://us.php.net/manual/en/language.types.type-juggling.php
(bool) or (boolean) is allowed for type casting a variable. No function like intval, etc but the functionality exists.
emanueledelgrande at email dot it
23-May-2007 01:12
23-May-2007 01:12
I think there's a hole in the PHP typecasting methods:
you have the (int) function, the (float) function and the (string) function, but no function to force a string variable into the boolean type.
It's obvious that forcing unconditionally the type of variables into arrays and objects is inappropriate, but boolean type is the most basic one for each programming language, that's why I guessed that a (bool) function already existed.
Moreover, with the increasing trend of RSS data streaming, the parsing of an XML string into an object often requires to typecast as boolean values the content of XML tags, normally returned as string by the object method get_content().
I wrote the following function, which also uses a "native PHP style" error message:
<?php
// strings tyecasting as boolean values:
function bool($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 08:12
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
23-May-2005 03:17
23-May-2005 03:17
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.