What are the best practices for naming variables in PHP to improve code readability and maintainability?

When naming variables in PHP, it is important to follow certain best practices to improve code readability and maintainability. Some common guidelines include using descriptive names that clearly convey the purpose of the variable, using camelCase or snake_case for multi-word variable names, avoiding abbreviations or overly generic names, and being consistent with naming conventions throughout the codebase.

// Example of using descriptive names and camelCase for variable naming
$userName = "JohnDoe";
$userAge = 30;

// Example of avoiding abbreviations and using snake_case for variable naming
$first_name = "John";
$last_name = "Doe";

// Example of being consistent with naming conventions
$employeeId = 1234;
$employeeDepartment = "HR";