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(PHP 4, PHP 5)
gettype — Liefert den Datentyp einer Variablen
Liefert den Datentyp einer Variablen. var.
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.
Die Variable, deren Typ ermittelt werden soll.
Mögliche Werte der zurückgegebenen Zeichenkette sind:
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
I wanted to compare the type of 2 vars.
1st method: Use this Funktion (gettype) and compare with ==
2nd method: Compare every type per is_[type]
Here a little Benchmark:
(I had to break line twice..)
<?php
$var1 = "Hallo";
$var2 = "Käsekuchen";
$var3 = 3.141526;
$Start = microtime(true);
for($i=0;$i<10000;$i++)
{
if(is_bool($var1)&&is_bool($var2)||is_int($var1)&&
is_int($var2)||is_string($var1)&&is_string($var2)||
is_object($var1)&&is_object($var2)||is_array($var1)
&&is_array($var2))
{
//same
}
if(is_bool($var3)&&is_bool($var2)||is_int($var3)&&
is_int($var2)||is_string($var3)&&is_string($var2)||
is_object($var3)&&is_object($var2)||is_array($var3)
&&is_array($var2))
{
//same
}
}
$time = microtime(true)-$Start;
echo "Zeit fuer if abfrage: ".$time."<br>";
$Start = microtime(true);
for($i=0;$i<10000;$i++)
{
if(gettype($var1)==gettype($var2))
{
//same
}
if(gettype($var3)==gettype($var2))
{
//same
}
}
$time = microtime(true)-$Start;
echo "Zeit fuer funktion : ".$time;
?>
Output:
Zeit fuer if abfrage: 0.0257611274719
Zeit fuer funktion : 0.0139331817627
So the function isnt so slow...
Lukas
After some testing I found a bug in my function "myGetType":
The check for "is_callable" was done before "is_string", so that something like <?php echo myGetType("max"); ?> would output: "function reference" instead of "string"
"is_callable" and "is_string" can't be checked together in this method, so I've removed the check for is_callable because it's a very rare usage case and if it's a valid string the check for is_callable never executes because is_string would be reached first (or vice-versa).
So here is the new function without "is_callable"-Check:
<?php
/**
* Returns the type of the var passed.
*
* @param mixed $var Variable
* @return string Type of variable
*/
function myGetType($var)
{
if (is_array($var)) return "array";
if (is_bool($var)) return "boolean";
if (is_float($var)) return "float";
if (is_int($var)) return "integer";
if (is_null($var)) return "NULL";
if (is_numeric($var)) return "numeric";
if (is_object($var)) return "object";
if (is_resource($var)) return "resource";
if (is_string($var)) return "string";
return "unknown type";
}
?>
This is my work around for the gettype warning. Hope some find it useful.
<?php
/**
* Returns the type of the passed var
* - PHP warns against using gettype(), this is my workaround
*
* @param mixed $var
* @return string
*/
function myGetType($var)
{
if (is_array($var)) return "array";
if (is_bool($var)) return "boolean";
if (is_callable($var)) return "function reference";
if (is_float($var)) return "float";
if (is_int($var)) return "integer";
if (is_null($var)) return "NULL";
if (is_numeric($var)) return "numeric";
if (is_object($var)) return "object";
if (is_resource($var)) return "resource";
if (is_string($var)) return "string";
return "unknown type";
}
?>
[EDITOR thiago NOTE: Code has been updated by PPKu-N0-SPAM-schy at mediasoft-berlin dot de]
In some rare cases a class instance object returns false when an object but gettype() returns "object".
<?php
$x = new classvar();
$save = serialize($x);
// ......
$obj = unserialize($save);
// here sometimes is_object() returns FALSE
if (is_object($x) || gettype($x) === "object")
{
// ... do something
}
?>
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
?>
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($number4);
?>
This will return:
-1.#IND
1
boolean
double
integer
boolean
0
1
1
0
PHP Warning: Division by zero in C\test.php on line 2 PHP Warning: Division by zero in C:\test.php on line 5
Here is something that had me stumped with regards to gettype and is_object.
Gettype will report an incomplete object as such, whereas is_object will return FALSE.
<?php
if (!is_object($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
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