PHP
In-class access with $this
Learn to access the class's properties and methods with the $this pseudo-variable.
What is $this?
$this is a special variable (pseudo-variable) that refers to the current instance inside a method. When a method is called on an instance, $this represents that instance.
To access a property from inside a method you write $this->name. Here -> is the object access operator. The $ sign is used only before $this; it is not written before the property name.
Accessing methods and properties with $this
With $this you can access not only properties but also other methods of the class. A method call is written $this->greet().
Example: in a Greeter class, the greet method reaches the $name property via $this->name and prints a greeting. Without $this, writing just $name makes PHP look for a local variable and miss the property.
Exercise Write the Greeter class with $this
Define a class named Greeter. Add the property public $name = "Guest";. Write a method greet; in the body write echo "Hello, " . $this->name . "!\n";. Do not call the method. After the class, write echo "Greeter ready" . "\n";.
Show example solution
Inside class Greeter { } add the property, then function greet() { echo ... $this->name ...; }, then echo after the class.
Example solution:
<?php
// Write the Greeter class, the $name property and the greet method
class Greeter {
public $name = "Guest";
function greet() {
echo "Hello, " . $this->name . "!\n";
}
}
echo "Greeter ready" . "\n";
Test yourself
-
Which is true about $this?
- $this represents all instances of a class.
- $this gives the name of the class.
- $this refers to the parent class.
- $this refers to the current instance.
Show answer
$this refers to the current instance. — Correct. $this refers to the current instance, giving access to properties and methods.
-
Complete the property access with $this
class Greeter {
public $name = "Guest";
function greet() {
echo "Hello, " . ____->name . "!";
}
}
Show answer
class Greeter {
public $name = "Guest";
function greet() {
echo "Hello, " . $this->name . "!";
}
}
-
Match the $this usage
- $this
- Reference to instance
- ->
- Access operator
- $this->name
- Property access
- $this->greet()
- Method call
Next lesson: Instantiating with new
