var_export
(PHP 4 >= 4.2.0, PHP 5)
var_export — Outputs or returns a parsable string representation of a variable
Beschreibung
var_export() gets structured information about the given variable. It is similar to var_dump() with one exception: the returned representation is valid PHP code.
Parameter Liste
- expression
-
The variable you want to export.
- return
-
If used and set to TRUE, var_export() will return the variable representation instead of outputing it.
Hinweis: This function internally uses the output buffering with this parameter so it can not be used inside ob_start() callback function.
Rückgabewerte
Returns the variable representation when the return parameter is used and evaluates to TRUE. Otherwise, this function will return NULL.
ChangeLog
| Version | Beschreibung |
|---|---|
| 5.1.0 | Possibility to export classes and arrays containing classes using the __set_state magic method. |
Beispiele
Example#1 var_export() Examples
<?php
$a = array (1, 2, array ("a", "b", "c"));
var_export($a);
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
array ( 0 => 1, 1 => 2, 2 => array ( 0 => 'a', 1 => 'b', 2 => 'c', ), )
<?php
$b = 3.1;
$v = var_export($b, true);
echo $v;
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
3.1
Example#2 Exporting classes since PHP 5.1.0
<?php
class A { public $var; }
$a = new A;
$a->var = 5;
var_export($a);
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
A::__set_state(array( 'var' => 5, ))
Example#3 Using __set_state (since PHP 5.1.0)
<?php
class A
{
public $var1;
public $var2;
public static function __set_state($an_array)
{
$obj = new A;
$obj->var1 = $an_array['var1'];
$obj->var2 = $an_array['var2'];
return $obj;
}
}
$a = new A;
$a->var1 = 5;
$a->var2 = 'foo';
eval('$b = ' . var_export($a, true) . ';'); // $b = A::__set_state(array(
// 'var1' => 5,
// 'var2' => 'foo',
// ));
var_dump($b);
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
object(A)#2 (2) { ["var1"]=> int(5) ["var2"]=> string(3) "foo" }
Anmerkungen
Hinweis: Variables of type resource couldn't be exported by this function.
Hinweis: var_export() does not handle circular references as it would be close to impossible to generate parsable PHP code for that. If you want to do something with the full representation of an array or object, use serialize().