get_resource_type
In some rare cases a class instance object returns false when an object but gettype() returns "object".
$x = new classvar();
$save = serialize($x);
......
$obj = unserialize($save);
// here sometimes is_object() returns FALSE
if (is_object($x) || gettype($x) === "object")
{
... do something
}
gettype
(PHP 4, PHP 5)
gettype — Liefert den Datentyp einer Variablen
Beschreibung
Liefert den Datentyp einer Variablen. var .
Warnung
Benutzen Sie gettype() niemals, um auf einen bestimmten Typ zu prüfen, da die zurückgegebene Zeichenkette irgendwann geändert werden könnte. Außerdem ist diese Methode langsam, da sie einen Vergleich von Zeichenketten benutzt.
Verwenden Sie stattdessen die is_*-Funktionen.
Parameter-Liste
- var
-
Die Variable, deren Typ ermittelt werden soll.
Rückgabewerte
Mögliche Werte der zurückgegebenen Zeichenkette sind:
- "boolean"
- "integer"
- "double" (aus historischen Gründen wird "double" im Fall eines float zurückgegeben, und nicht einfach float.
- "string"
- "array"
- "object"
- "resource"
- "NULL"
- "unknown type"
Beispiele
Beispiel #1 gettype()-Beispiel
<?php
$data = array(1, 1., NULL, new stdClass, 'foo');
foreach ($data as $value) {
echo gettype($value), "\n";
}
?>
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
integer double NULL object string
add a note
User Contributed Notesgettype
skatebiker at hotmail dot com
22-Feb-2008 03:51
22-Feb-2008 03:51
sneskid at hotmail dot com
05-Mar-2007 11:56
05-Mar-2007 11:56
I wrote my own gettype function by just using the default is_? functions, but it took twice as long as gettype... So I decided to use gettype with a twist.
Taking the warnings about gettype to heart, and depending on your custom needs, it's worthwhile to dynamically test the gettype result with a known variable, and link the result to a predefined result. Like so:
<?php
/*
dynamically create an array by using known variable types
link with a predefined value
*/
$R=array();
$R[gettype(.0)]='number';
$R[gettype(0)]='number';
$R[gettype(true)]='boolean';
$R[gettype('')]='string';
$R[gettype(null)]='null';
$R[gettype(array())]='array';
$R[gettype(new stdClass())]='object';
// what is
function wis_($v){
global $R;
return $R[gettype($v)];
}
echo wis_('hello') . '<br/>'; // "string"
echo wis_(24) . '<br/>'; // "number"
echo wis_(0.24) . '<br/>'; // "number"
echo wis_(null) . '<br/>'; // "null"
echo wis_($R) . '<br/>'; // "array"
?>
You won't need to worry about changes in gettype's return strings in future versions.
If the result evaluates to false then you know the variable tested is some "other" type.
I also find these useful
<?php
function is_num($v){return (is_int($v) || is_double($v));}
function is_box($v){return (is_array($v)||is_object($v));}
echo is_num(null) . '<br/>'; // false
echo is_num(false) . '<br/>'; // false
echo is_num('123') . '<br/>'; // false
echo is_num(123) . '<br/>'; // true
echo is_num(123.0) . '<br/>'; // true
?>
gilthansNOSPAM at gmail dot com
11-Sep-2005 11:18
11-Sep-2005 11:18
NaN and #IND will return double or float on gettype, while some inexistent values, like division by zero, will return as a boolean FALSE. 0 by the 0th potency returns 1, even though it is mathematically indetermined.
<?php
$number = 5/0;
$number2 = sqrt(-3);
$number3 = pow(0, 0);
$number4 = 0/0;
echo $number."<br />";
echo $number2."<br />";
echo $number3."<br />";
echo $number4."<br />";
echo "<br />";
echo gettype($number)."<br />";
echo gettype($number2)."<br />";
echo gettype($number3)."<br />";
echo gettype($number4);
?>
This will return:
-1.#IND
1
boolean
double
integer
boolean
0
1
1
0
PHP Warning: Division by zero in C\test.php on line 2 PHP Warning: Division by zero in C:\test.php on line 5
matt at appstate
16-Dec-2004 09:10
16-Dec-2004 09:10
Here is something that had me stumped with regards to gettype and is_object.
Gettype will report an incomplete object as such, whereas is_object will return FALSE.
if (!is_object($incomplete_obj)) {
echo 'This variable is not an object, it is a/an ' . gettype($incomplete_obj);
}
Will print:
This variable is not an object, it is a/an object