How to Set a Variable in PHP


A variable in PHP is a name that represents a value or data. You can think of it as a storage location for information that your script can access and manipulate. Variables can hold various types of data, such as numbers, strings, or arrays.

Setting a Variable

To set a variable in PHP, you use the assignment operator (=). Here’s the basic syntax:

$variable_name = value;
  • $variable_name: This is the name you choose for your variable. It must start with a dollar sign $, followed by letters, numbers, or underscores.
  • value: This is the data or value you want to store in the variable.

Let’s look at some examples:

$name = "John";
$age = 30;
$isStudent = true;

In this code, we’ve created three variables: $name, $age, and $isStudent, each storing different types of data.

Data Types

PHP supports various data types, and the type of data a variable can hold depends on what you assign to it. Some common data types include:

  • Strings: Used for text, enclosed in single or double quotes.
  • Integers: Used for whole numbers, e.g., 5 or 42.
  • Floats: Used for decimal numbers, e.g., 3.14.
  • Booleans: Used for true/false values, e.g., true or false.
  • Arrays: Used for storing lists of data.
  • Objects: Used for creating custom data structures.

Here are some examples of setting variables of different types:

$name = "Alice";        // String
$age = 25;              // Integer
$price = 9.99;          // Float
$isStudent = true;      // Boolean
$fruits = ["apple", "banana", "cherry"]; // Array

class Person {
    public $name;
    public $age;
}

$person1 = new Person();
$person1->name = "Alice";
$person1->age = 30;

Variable Naming Rules

When naming variables in PHP, you should adhere to some rules:

  • Variable names are case-sensitive, so $name and $Name are considered different variables.
  • Variable names must start with a letter or underscore, followed by letters, numbers, or underscores.
  • Avoid using PHP reserved words like echo, if, or while as variable names.
  • Choose descriptive names that make your code more readable. For example, use $username instead of $u for storing a user’s name.