constant
Returns the value of a constant by its name in a string.
Syntax
constant(string $name): mixedParameters
| Parameter | Type | Description |
|---|---|---|
| $name | string | The constant name; for a class constant, `Class::NAME`. |
Return value
mixedThe value of the constant.
Examples
A constant name in a variable:
<?php
class Status
{
public const ACTIVE = 'active';
public const BLOCKED = 'blocked';
}
$name = 'BLOCKED';
echo constant('Status::' . $name), ' ', constant('E_USER_ERROR');Output:
blocked 256Notes
If the constant does not exist, the function throws an Error. For a set of related values an enum is handier.
See also
- define — Creates a constant at run time.
- defined — Checks whether a constant exists.
- call_user_func — Calls a function held in a variable.
Related recipes
In the tutorial
- Constants — Constants in PHP — const and define, naming rules, built-in and magic constants.