PHP Variables

Declaring Variables

All variables in PHP start with a $ symbol followed by the variable name:

$name = "Alice";
$age = 25;
$price = 9.99;

Naming Rules

• Start with a letter or underscore
• Cannot start with a number
• Can contain letters, numbers, and underscores
• Are case-sensitive

$UserName ≠ $username

Variable Scope

PHP has three main scopes:

• Local: Inside a function
• Global: Outside any function
• Static: Preserves a local variable’s value between calls

Variable Variables

You can use one variable to name another (dynamic variable):

$name = "PHP";
$$name = "Rocks";

echo $PHP;  // Outputs: Rocks

Use cautiously — this can make code harder to read.

Variable Reassignment

You can freely reassign variables to different types:

$x = 5;
$x = "now a string";

This is allowed because PHP is dynamically typed.

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