var_export

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

var_exportOutputs or returns a parsable string representation of a variable

Опис

var_export(mixed $value, bool $return = false): ?string

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.

Параметри

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.

Значення, що повертаються

Returns the variable representation when the return parameter is used and evaluates to true. Otherwise, this function will return null.

Журнал змін

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.

Приклади

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"
}

Примітки

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().

Увага

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.

Прогляньте також

  • print_r() - Prints human-readable information about a variable
  • serialize() - Generates a storable representation of a value
  • var_dump() - Виводить інформацію про змінну