(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
var_export — Outputs or returns a parsable string representation of a variable
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.
value
The variable you want to export.
return
If used and set to true
, var_export() will return
the variable representation instead of outputting it.
Returns the variable representation when the return
parameter is used and evaluates to true
. Otherwise, this function will
return null
.
Версія | Опис |
---|---|
8.2.0 | Exported class names are now fully qualified; previously, the leading backslash was ommitted. |
7.3.0 |
Now exports stdClass objects as an array cast to
an object ((object) array( ... ) ), rather than using the
nonexistent method stdClass::__setState().
The practical effect is that now stdClass is
exportable, and the resulting code will even work on earlier versions of
PHP.
|
Приклад #1 var_export() Examples
<?php
$a = array (1, 2, array ("a", "b", "c"));
var_export($a);
?>
Поданий вище приклад виведе:
array ( 0 => 1, 1 => 2, 2 => array ( 0 => 'a', 1 => 'b', 2 => 'c', ), )
<?php
$b = 3.1;
$v = var_export($b, true);
echo $v;
?>
Поданий вище приклад виведе:
3.1
Приклад #2 Exporting stdClass (since PHP 7.3.0)
<?php
$person = new stdClass;
$person->name = 'ElePHPant ElePHPantsdotter';
$person->website = 'https://php.net/elephpant.php';
var_export($person);
Поданий вище приклад виведе:
(object) array( 'name' => 'ElePHPant ElePHPantsdotter', 'website' => 'https://php.net/elephpant.php', )
Приклад #3 Exporting classes
<?php
class A { public $var; }
$a = new A;
$a->var = 5;
var_export($a);
?>
Поданий вище приклад виведе:
A::__set_state(array( 'var' => 5, ))
Приклад #4 Using __set_state()
<?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);
?>
Поданий вище приклад виведе:
object(A)#2 (2) { ["var1"]=> int(5) ["var2"]=> string(3) "foo" }
Зауваження:
Variables of type resource couldn't be exported by this function.
Зауваження:
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().
Prior to PHP 8.2.0, when var_export() exports objects, the leading backslash is not included in the class name of namespaced classes for maximum compatibility.
Зауваження:
To be able to evaluate the PHP generated by var_export(), all processed objects must implement the magic __set_state method. The only exception is stdClass, which is exported using an array cast to an object.