How is the comparison of objects done in PHP?

In PHP, objects are compared using the "identity" operator === or the "equality" operator ==. The identity operator checks whether two objects are the same instance, while the equality operator checks whether two objects have the same properties and values.

When using the identity operator (===), two objects are considered equal only if they are the same instance of the same class. In other words, two objects are identical only if they occupy the same memory address. Here is an example:

In this example, $obj1 and $obj2 are not identical, because they are two different instances of the MyClass class. However, $obj1 and $obj3 are identical, because they refer to the same instance of the MyClass class.

When using the equality operator (==), two objects are considered equal if they have the same properties and values, even if they are not the same instance of the same class. Here is an example:

In this example, $obj1 and $obj2 have the same properties and values, even though they are two different instances of the MyClass class. Therefore, they are considered equal when compared with the equality operator.

It's important to note that comparing objects in PHP can sometimes be tricky, especially when dealing with objects that have complex properties or reference other objects. In general, it's a good practice to test object comparison behavior thoroughly and use appropriate operators depending on the specific use case.