get_defined_constants
(PHP 4 >= 4.1.0, PHP 5)
get_defined_constants — Returns an associative array with the names of all the constants and their values
Description
$categorize = false
] )Returns the names and values of all the constants currently defined. This includes those created by extensions as well as those created with the define() function.
Parameters
-
categorize -
Causing this function to return a multi-dimensional array with categories in the keys of the first dimension and constants and their values in the second dimension.
<?php
define("MY_CONSTANT", 1);
print_r(get_defined_constants(true));
?>The above example will output something similar to:
Array ( [Core] => Array ( [E_ERROR] => 1 [E_WARNING] => 2 [E_PARSE] => 4 [E_NOTICE] => 8 [E_CORE_ERROR] => 16 [E_CORE_WARNING] => 32 [E_COMPILE_ERROR] => 64 [E_COMPILE_WARNING] => 128 [E_USER_ERROR] => 256 [E_USER_WARNING] => 512 [E_USER_NOTICE] => 1024 [E_ALL] => 2047 [TRUE] => 1 ) [pcre] => Array ( [PREG_PATTERN_ORDER] => 1 [PREG_SET_ORDER] => 2 [PREG_OFFSET_CAPTURE] => 256 [PREG_SPLIT_NO_EMPTY] => 1 [PREG_SPLIT_DELIM_CAPTURE] => 2 [PREG_SPLIT_OFFSET_CAPTURE] => 4 [PREG_GREP_INVERT] => 1 ) [user] => Array ( [MY_CONSTANT] => 1 ) )
Return Values
Returns an array of constant name => constant value array, optionally groupped by extension name registering the constant.
Changelog
| Version | Description |
|---|---|
| 5.3.1 | Windows only: Core constants are categorized under Core, previously mhash. |
| 5.3.0 | Core constants are categorized under Core, previously internal. On Windows, the Core Constants are categorized under mhash. |
| 5.2.11 |
The categorize parameter now operates appropriately.
Previously, the categorize parameter was interpreted
as !is_null($categorize), making any value other than NULL
force the constants to be categorized.
|
| 5.0.0 |
The categorize parameter was added.
|
Examples
Example #1 get_defined_constants() Example
<?php
print_r(get_defined_constants());
?>
The above example will output something similar to:
Array
(
[E_ERROR] => 1
[E_WARNING] => 2
[E_PARSE] => 4
[E_NOTICE] => 8
[E_CORE_ERROR] => 16
[E_CORE_WARNING] => 32
[E_COMPILE_ERROR] => 64
[E_COMPILE_WARNING] => 128
[E_USER_ERROR] => 256
[E_USER_WARNING] => 512
[E_USER_NOTICE] => 1024
[E_ALL] => 2047
[TRUE] => 1
)
See Also
- defined() - Checks whether a given named constant exists
- get_loaded_extensions() - Returns an array with the names of all modules compiled and loaded
- get_defined_functions() - Returns an array of all defined functions
- get_defined_vars() - Returns an array of all defined variables
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Изменение поведения PHP
- PHP Опции и Информация
- assert_options
- assert
- cli_get_process_title
- cli_set_process_title
- dl
- extension_loaded
- gc_collect_cycles
- gc_disable
- gc_enable
- gc_enabled
- gc_mem_caches
- get_cfg_var
- get_current_user
- get_defined_constants
- get_extension_funcs
- get_include_path
- get_included_files
- get_loaded_extensions
- get_magic_quotes_gpc
- get_magic_quotes_runtime
- get_required_files
- get_resources
- getenv
- getlastmod
- getmygid
- getmyinode
- getmypid
- getmyuid
- getopt
- getrusage
- ini_alter
- ini_get_all
- ini_get
- ini_restore
- ini_set
- magic_quotes_runtime
- main
- memory_get_peak_usage
- memory_get_usage
- php_ini_loaded_file
- php_ini_scanned_files
- php_logo_guid
- php_sapi_name
- php_uname
- phpcredits
- phpinfo
- phpversion
- putenv
- restore_include_path
- set_include_path
- set_magic_quotes_runtime
- set_time_limit
- sys_get_temp_dir
- version_compare
- zend_logo_guid
- zend_thread_id
- zend_version
Коментарии
<?php/**
* Convert constant value into string name.
*
* @param mixed Constant value.
* @return string Constant name.
* @access public
*/
function sch_get_consant($value)
{
$constants = get_defined_constants();
$name = array_search($value, $constants, TRUE);
return $name;
}
?>
If you want to filter through and return only the prefix for your constants (i.e. you have constants with a naming scheme), then you can use this quick little function. It comes in handy for debugging.
<?php
function returnConstants ($prefix) {
foreach (get_defined_constants() as $key=>$value)
if (substr($key,0,strlen($prefix))==$prefix) $dump[$key] = $value;
if(empty($dump)) { return "Error: No Constants found with prefix '".$prefix."'"; }
else { return $dump; }
}
?>
Example:
<?php
define("SITENAME_OPTION_ONE",true);
define("SITENAME_OPTION_TWO",false);
define("SITENAME_URL","foo");
print_r(returnConstants("SITENAME_OPTION"));
?>
Will return:
Array
(
[SITENAME_OPTIONONE] => 1
[SITENAME_OPTIONTWO] =>
)
Add this method to your class definition if you want an array of class constants (get_defined_constants doesn't work with class constants as Peter P said above):
<?php
public function get_class_constants()
{
$reflect = new ReflectionClass(get_class($this));
return $reflect->getConstants());
}
?>
You could also override stdObject with it so that all your classes have this method
If you want to access directly on one category, just use:
<?php
print_r(get_defined_constants(true)['Core']);
?>
you can replace 'Core' by the category you wish (e.g. user):
<?php
print_r(get_defined_constants(true)['user']);
?>
Warning: only use this on development side
If you want to create a static method that you can copy and paste into each class you have constants created, you can use:
<php
public static function get_class_constants(): array
{
$reflect = new ReflectionClass(self::class);
return $reflect->getConstants();
}
?>