Proposal: Create a function get_class_constants() It would be similar to get_class_methods() and get_class_vars(). constants class in php.
You have to use the PHP keyword 'const' and initialize it with a scalar value -- boolean, int, float, string (or array in PHP 5.6+) -- right away. Accessing PHP Class Constants (3) . Previous Page. Advertisements.
Class constants are case-sensitive. (13 replies) Hi, following the howto for RFCs and since this would be my first one, I'd like to ask for your thoughts if such an RFC might find approval.
The value cannot be changed during the script. A constant value cannot change during the execution of the script. It is possible to define constants as a resource, but it should be avoided, as it can cause unexpected results. If yes, I'll be happy to work on it. From PHP 5.6 onwards, it is possible to define a constant as a scalar expression, and it is also possible to define an array constant. A constant is a name or an identifier for a simple value. If yes, I'll be happy to work on it. By convention, constant identifiers are always uppercase.
PHP has the function get_defined_constants() which allows you to get a list of all the available constants in an array. PHP interfaces allow the definition of constants in an interface, e.g. Constants cannot be changed once it is declared. CONSTANTS and PHP Class Definitions Using "define('MY_VAR', 'default value')" INSIDE a class definition does not work as expected. A class constant is declared inside a class with the const keyword. Note that with this approach you might get some other constant that the one you want, if there are two constants with the same value. This post looks at how to use the get_defined_constants() function and example output from it. I once heard it's good to have one class with all your application constants so that you have only one location with all your constants. class MyFooBar implement FooBar { } echo MyFooBar::FOO; // 1 My own take on this is that anything Global is Evil. – halfer Apr 29 '12 at 0:17 PHP What is OOP PHP Classes/Objects PHP Constructor PHP Destructor PHP Access Modifiers PHP Inheritance PHP Constants PHP Abstract Classes PHP Traits PHP Static Methods PHP Static Properties MySQL Database MySQL Database MySQL Connect MySQL Create DB MySQL Create Table MySQL Insert Data MySQL Get Last ID MySQL Insert Multiple MySQL Prepared MySQL Select Data MySQL Where … Active 1 year, 5 months ago. I'm attempting to get a list of class constants from within a static method. interface FooBar { const FOO = 1; const BAR = 2; } echo FooBar::FOO; // 1 Any implementing class will automatically have these constants available, e.g. The PHP manual says . However, it is recommended to name the constants in all uppercase letters. example: A constant is an identifier (name) for a simple value. Best workaround to create a PHP class constant from an expression?
PHP - Constants Types. Edit: the short answer to your question is no. Get all the constants defined in the class, loop over them and compare the values of those constants with the value of your variable. Proposal for RFC: get_class_constants() Groups: php.internals : Hi, following the howto for RFCs and since this would be my first one, I'd like to ask for your thoughts if such an RFC might find approval. But I can't create a class constant from an expression like that: The value must be a constant expression, not (for example) a variable, a property, a result of a mathematical operation, or a function call. PHP Constants. The get_defined_constants() function takes one optional parameter, which specifies whether or not to categorise the constants. A valid constant name starts with a letter or underscore (no $ sign before the constant name).
Ask Question Asked 10 years, 11 months ago. Class constants can be useful if you need to define some constant data within a class. I Tried to do it this way: class constants{ define("EH_MAILER",1); } and . get_object_constants and get_class_constants Currently this can only be done through ReflectionClass which is far slower than retrieving them directly from the constants table. Note: Unlike variables, constants are automatically global across the entire script.
Either define a constant in the abstract class (thus every child class has a constant, even if it does not define its own), or use an abstract function (which forces every child class to define its own). Viewed 3k times 3. Like static members, constant values can not be accessed from an instance of the object. By default, a constant is case-sensitive.