What are the rules for naming variables in PHP?

Variables in PHP are fundamental elements used for storing data and performing operations within scripts. To maintain clarity and enhance maintainability in your codebase, it’s imperative to adhere to certain naming conventions and guidelines:

Syntax:

// Valid variable name
$myVariable; 

// Valid variable name starting with an underscore  
$_myVariable;  

// Valid variable name using underscores
$my_variable;  

// Valid variable name with numbers
$myVariable123; 

// Valid variable name starting with an underscore and numbers
$_123Variable; 

// Valid variable name, but different from $myVariable (case-sensitive)
$MyVariable;  

Rules:

• Valid Characters:
  • Variables can comprise letters (a-z, A-Z), numbers (0-9), and underscores (_).
  • They must commence with a letter or underscore, not a number.
• Case Sensitivity:
  • PHP variable names are case-sensitive. For instance, $variableName and $VariableName are considered distinct.
• Avoid Reserved Keywords:
  • Refrain from using PHP-reserved keywords such as if, else, for, etc., as variable names, as they serve specific purposes in the language.
• Descriptive and Meaningful:
  • Opt for descriptive and meaningful names that convey the purpose or content of the variable.
  • Utilize camelCase or snake_case conventions for multi-word variable names, maintaining consistency within your code.
• Clear and Concise:
  • Keep variable names concise while ensuring they accurately represent the data they store or the functionality they support.