__get and __set for property access in PHP - Step-by-Step Execution

Concept Flow - __get and __set for property access

Access property obj->prop

↓

Is property accessible?

Yes→Return property value

No↓

Call __get('prop')

↓

Return value from __get

↓

Assign obj->prop = value

↓

Is property accessible?

Yes→Set property value

No↓

Call __set('prop', value)

↓

Store value in __set

When you try to get or set a property that is not accessible, PHP calls __get or __set methods to handle it.

Execution Sample

PHP

<?php
class Person {
  private $data = [];
  public function __get($name) {
    return $this->data[$name] ?? 'Not set';
  }
  public function __set($name, $value) {
    $this->data[$name] = $value;
  }
}
$p = new Person();
$p->age = 30;
echo $p->age;
echo $p->name;
?>

This code sets and gets a property 'age' using __set and __get because 'age' is not a declared property.

Execution Table

Step	Action	Property	Value	Method Called	Result/Output
1	Assign property	age	30	__set	Stores 30 in data['age']
2	Access property	age		__get	Returns 30
3	Output				30
4	Access undefined property	name		__get	Returns 'Not set'
5	Output				Not set

💡 No more code to execute, program ends.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 4	Final
data	[]	{"age":30}	{"age":30}	{"age":30}	{"age":30}
age	undefined	30	30	30	30
name	undefined	undefined	undefined	undefined	undefined

Key Moments - 3 Insights

Why does PHP call __set when assigning to $p->age?

Because 'age' is not a declared property, PHP calls __set to handle the assignment, as shown in execution_table step 1.

Why does accessing $p->age call __get instead of returning a property directly?

Since 'age' is not declared, PHP calls __get to retrieve the value, as shown in execution_table step 2.

What happens if you access a property that was never set?

The __get method returns 'Not set' as a default, shown in execution_table step 4 and 5.

Visual Quiz - 3 Questions

Look at the execution_table, what method is called when assigning $p->age = 30?

A __set

B __get

C No method, direct assignment

D __construct

💡 Hint

Check execution_table step 1 where assignment triggers __set.

At which step does accessing an undefined property return 'Not set'?

A Step 1

B Step 2

C Step 4

D Step 3

💡 Hint

See execution_table step 4 where __get returns 'Not set'.

If the property 'age' was declared public, what would happen when assigning $p->age = 30?

A __set would still be called

B Direct assignment without __set

C __get would be called

D Error occurs

💡 Hint

Refer to concept_flow: __set is called only if property is inaccessible.

Concept Snapshot

__get and __set are magic methods in PHP.
They run when accessing or setting inaccessible properties.
__get($name) returns a value for $obj->$name.
__set($name, $value) sets a value for $obj->$name.
Use them to control dynamic property access safely.

Full Transcript

This example shows how PHP uses __get and __set when you try to get or set a property that is not declared or accessible. When you assign a value to such a property, __set is called to handle storing the value. When you read such a property, __get is called to return a value. If the property was never set, __get can return a default like 'Not set'. This lets you control how your object handles properties dynamically.