PHP Constants are global variables whose value cannot be changed during execution and can only store scalar values.
Constants are defined using the
define($name, $value) function.
PHP Constants Example
PHP Constants Naming Convension
Unlike variables, PHP Constants do not need to start with the dollar sign($). Constants once defined cannot be changed during compile time. Constants are widely written in uppercase and must start with either a letter or an underscore.
PHP Constants Naming Convention Example
defined(string $constantName):bool is a function that checks if a constant exists. It only applies to constants unlike
isset() which can be used to check if a variable exists It returns true if a constant is already defined or false if it does not.
PHP Constants defined() Function
What You Should Know at the End of This Lesson
- You should know how to define a PHP constant.
- You should how the PHP constant naming convention works.
- You should know how to check if a constant exists with