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

Beskrivelse

array get_defined_constants ([ bool $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.

Parametre

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
        )

)

Returnerings Værdier

ChangeLog

Version	Beskrivelser
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.

Eksempler

Eksempel #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
)

Se også

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

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User Contributed Notes 4 notes

down

Bob ¶

15 years ago


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

down

R4FC0R3 ¶

6 years ago


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

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me at gogogadgetscott dot info ¶

18 years ago


<?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;
}
?>

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Anonymous ¶

18 years ago


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] => 
)

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