Given a DateTime object and the task is to create a copy of that object. To create a copy of DateTime object we use clone keyword which is described below:
A copy of DateTime object is created by using the clone keyword (which calls the object’s __clone() method if possible). An object’s __clone() method cannot be called directly. When an object is cloned, PHP will perform a shallow copy of all of the object’s properties. Any properties that are references to other variables will remain references.
Syntax:
$DateTime_copy_object_name = clone $DateTime_object_to_be_copied
Below examples illustrate the cloning of DateTime object in PHP:
Example 1:
PHP
<?php // Program to create copy of DateTime object // Creating object $obj = new DateTime();// Creating clone or copy of object $copy = clone $obj; // Printing initial valuesecho "Printing initial values\n";$result = $obj->format('Y-m-d H:i:s');echo "Original object: $result\n";$result = $copy->format('Y-m-d H:i:s');echo "Cloned object: $result\n\n";// Changing original object ($obj) value// to verify other($copy) is clone or not// This statement will add 3 Days$obj->add(new DateInterval('P3D'));// Printing valuesecho "Printing values after change\n";$result = $obj->format('Y-m-d H:i:s');echo "Original object: $result\n";$result = $copy->format('Y-m-d H:i:s');echo "Cloned object: $result\n";?> |
Output:
Printing initial values Original object: 2020-04-14 17:14:18 Cloned object: 2020-04-14 17:14:18 Printing values after change Original object: 2020-04-17 17:14:18 Cloned object: 2020-04-14 17:14:18
Example 2: Below program distinguishes clone from assignment ( = ) operator.
PHP
<?php // Program to create copy of DateTime object // Creating object $obj = new DateTime();// Creating clone or copy of object $copy = clone $obj;$ref_obj = $obj;// Printing initial valuesecho "Printing initial values\n";$result = $obj->format('Y-m-d H:i:s');echo "Original object: $result\n";$result = $ref_obj->format('Y-m-d H:i:s');echo "Reference object: $result\n";$result = $copy->format('Y-m-d H:i:s');echo "Cloned object: $result\n\n";// Changing original object ($obj) value// to verify other($copy) is clone or not// This statement will add 3 Months$obj->add(new DateInterval('P3M'));// Printing valuesecho "Printing values after change\n";$result = $obj->format('Y-m-d H:i:s');echo "Original object: $result\n";$result = $ref_obj->format('Y-m-d H:i:s');echo "Reference object: $result\n";$result = $copy->format('Y-m-d H:i:s');echo "Cloned object: $result\n";?> |
Output:
Printing initial values Original object: 2020-04-14 17:14:49 Reference object: 2020-04-14 17:14:49 Cloned object: 2020-04-14 17:14:49 Printing values after change Original object: 2020-07-14 17:14:49 Reference object: 2020-07-14 17:14:49 Cloned object: 2020-04-14 17:14:49
So, to make a copy of the object we use clone, don’t use (=) operator as it creates a reference.
