PHP Inherit the properties of non-class object?

In PHP, you can inherit the structure (property names) of a non-class object while resetting the property values to null. This is useful when you need to create a new object with the same properties but empty values.

Method 1: Using clone and foreach

Clone the original object and then iterate through its properties to set them to null −

<?php
$firstObject = (object)[
    "Name" => "John",
    "Age" => 20
];

$secondObject = clone $firstObject;
echo "Original object:
";
var_dump($firstObject);

echo "\nCloned object:
";
var_dump($secondObject);

// Set all properties to null
foreach ($secondObject as $keyName => $keyValue) {
    $secondObject->$keyName = null;
}

echo "\nAfter setting properties to null:
";
var_dump($secondObject);
?>

Original object:
object(stdClass)#1 (2) {
  ["Name"]=>
  string(4) "John"
  ["Age"]=>
  int(20)
}

Cloned object:
object(stdClass)#2 (2) {
  ["Name"]=>
  string(4) "John"
  ["Age"]=>
  int(20)
}

After setting properties to null:
object(stdClass)#2 (2) {
  ["Name"]=>
  NULL
  ["Age"]=>
  NULL
}

Method 2: Using array_fill_keys()

Convert the object to array, extract keys, fill with null values, and convert back to object −

<?php
$firstObject = [
    "Name" => "John",
    "Age" => 20
];

// Create array with same keys but null values
$arrayObject = array_fill_keys(array_keys($firstObject), null);
$secondObject = (object)$arrayObject;

echo "Original array:
";
var_dump($firstObject);

echo "\nNew object with inherited structure:
";
var_dump($secondObject);
?>

Original array:
array(2) {
  ["Name"]=>
  string(4) "John"
  ["Age"]=>
  int(20)
}

New object with inherited structure:
object(stdClass)#1 (2) {
  ["Name"]=>
  NULL
  ["Age"]=>
  NULL
}

Comparison

Conclusion

Both methods effectively inherit the property structure while nullifying values. Use clone with foreach for objects and array_fill_keys() for arrays when creating object templates.