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] =>
)
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 valuesDescription
array get_defined_constants ( [mixed categorize] )This function 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.
For example the line below:
<?php |
will print a list like:
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
) |
As of PHP 5, an additional parameter, categorize, may be passed, 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 |
上例的输出类似于：
Array
(
[internal] => 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
)
) |
注: The value of the categorize parameter is irrelevant, only its presence is considered.
See also defined(), get_loaded_extensions(), get_defined_functions(), and get_defined_vars().
add a note
User Contributed Notes
06-Jan-2006 03:29
me at gogogadgetscott dot info
19-Jun-2005 02:14
19-Jun-2005 02:14
<?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;
}
?>