Be aware of what get_defined_vars() function returns in different contexts:
- In global scope, a list of all defined variables, whether superglobals, command line arguments or user-defined variables
- In function scope, only a list of user-defined variables (both arguments and in-body definitions)
- In class/object method scope, does not return class/object properties;
Also, as of PHP 5.4, does not return $_ENV even where available.
For further details and scope tests/results, see https://github.com/php/doc-en/issues/1317
get_defined_vars
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
get_defined_vars — Returns an array of all defined variables
Description
get_defined_vars(): array
This function returns a multidimensional array containing a list of all defined variables, be them environment, server or user-defined variables, within the scope that get_defined_vars() is called.
Parameters
This function has no parameters.
Return Values
A multidimensional array with all the variables.
Examples
Example #1 get_defined_vars() Example
<?php
$b = array(1, 1, 2, 3, 5, 8);
$arr = get_defined_vars();
// print $b
print_r($arr["b"]);
/* print path to the PHP interpreter (if used as a CGI)
* e.g. /usr/local/bin/php */
echo $arr["_"];
// print the command-line parameters if any
print_r($arr["argv"]);
// print all the server vars
print_r($arr["_SERVER"]);
// print all the available keys for the arrays of variables
print_r(array_keys(get_defined_vars()));
?>See Also
- isset() - Determine if a variable is declared and is different than null
- get_defined_functions() - Returns an array of all defined functions
- get_defined_constants() - Returns an associative array with the names of all the constants and their values
add a note
User Contributed Notes 20 notes
cmswares dot com at gmail dot com ¶
2 years ago
antonfedonyuk at gmail dot com ¶
3 years ago
NOTE: when you call code by eval() PHP append self vars to result, they have "__" prefix ("__source_code" and "__bootstrap_file" in PHP 7.3).
Fix:
<?php
function filter_eval_vars(array $vars): array
{
foreach ($vars as $key => $value) {
if ($key[0] === '_' && $key[1] === '_') {
unset($vars[$key]);
}
}
return $vars;
}
?>
Qiibow ¶
3 years ago
get_defined_vars() is very useful for importing many values at once
into another scope (Such as User-defined functions).
Below is an example for showing some of many values and their variable-names in a table.
(useful in debugging)
You can put this user-defined function at many places in your script
to show some values (values to be changed in loops)
to check if they are what they shall be there or not.
<?php
// Set "get_defined_vars()" to 2nd argument.
function get_value_table($name_array, $gdv) {
$name_value_table = [];
foreach ($name_array as $name) :
if (!array_key_exists($name, $gdv)) :
$value = 'undefined';
elseif (is_bool($gdv[$name])) :
$value = $gdv[$name]? 'true' : 'false';
elseif (is_numeric($gdv[$name]) || is_string($gdv[$name])) :
$value = $gdv[$name];
elseif (is_array($gdv[$name])) :
$value = '<pre>'.print_r($gdv[$name],true).'</pre>';
else :
$value = (PHP_VERSION_ID >= 80000)? get_debug_type($gdv[$name]) : get_type($gdv[$name]);
endif;
$name_value_table[] = '<tr><td>$'.$name.'<td>'.$value;
endforeach;
return '<table border=1>'.implode("\n", $name_value_table).'</table>';
} // (f) get_value_table()
$_1 = 'a';
$_2 = 'b';
$_3 = [1,2];
$_4 = false;
$_5 = null;
$name_array = ['_1','_2','_3','_4','_5','_6'];
$show_id = 1;
if ($show_id === 1) :
echo get_value_table($name_array, get_defined_vars());
endif;
/*
if $show_id === 1, only shows below.
$_1 a
$_2 b
$_3 Array
(
[0] => 1
[1] => 2
)
$_4 false
$_5 null
$_6 undefined
*/
$_2 = 'c';
if ($show_id === 2) :
echo get_value_table($name_array, get_defined_vars()); // $_2 c
endif;
# if $show_id === 2, $_2 turns "c".
?>
ryanlwh at yahoo dot com ¶
11 years ago
Since get_defined_vars() only gets the variables at the point you call the function, there is a simple way to get the variables defined within the current scope.
<?php
// The very top of your php script
$vars = get_defined_vars();
// Now do your stuff
$foo = 'foo';
$bar = 'bar';
// Get all the variables defined in current scope
$vars = array_diff(get_defined_vars(),$vars);
echo '<pre>';
print_r($vars);
echo '</pre>';
?>
zabmilenko at hotmail dot com ¶
18 years ago
A little gotcha to watch out for:
If you turn off RegisterGlobals and related, then use get_defined_vars(), you may see something like the following:
<?php
Array
(
[GLOBALS] => Array
(
[GLOBALS] => Array
*RECURSION*
[_POST] => Array()
[_GET] => Array()
[_COOKIE] => Array()
[_FILES] => Array()
)
[_POST] => Array()
[_GET] => Array()
[_COOKIE] => Array()
[_FILES] => Array()
)
?>
Notice that $_SERVER isn't there. It seems that php only loads the superglobal $_SERVER if it is used somewhere. You could do this:
<?php
print '<pre>' . htmlspecialchars(print_r(get_defined_vars(), true)) . '</pre>';
print '<pre>' . htmlspecialchars(print_r($_SERVER, true)) . '</pre>';
?>
And then $_SERVER will appear in both lists. I guess it's not really a gotcha, because nothing bad will happen either way, but it's an interesting curiosity nonetheless.
nix dot code at 4assistance dot com dot nix ¶
3 years ago
Insert this at point of interest; add keys of unwanted 1st dim variables to 2nd param of array_diff_key
<?php
echo '<pre>defined_except '; var_dump (array_diff_key (get_defined_vars(), ['GLOBALS'=>0,'_SERVER'=>0])); echo ' '.basename(__FILE__).':'.__LINE__.'</pre>'; #die;
?>
sergeyzuzic at mail dot ru ¶
9 years ago
dirty code sample:
print_r(compact(array_keys(get_defined_vars())));
mail at mkharitonov dot net ¶
10 years ago
Reference variables are returned by reference (tested on PHP 5.5.11):
<?php
$a = null;
$b = &$a;
get_defined_vars()['b'] = 4;
var_dump($b); // int(4)
?>
npelov at croler dot net ¶
3 years ago
get_defined_vars() returns all variables - locally defined vars and global vars (well actually only super globals). If you need local vars only - for example you need to get variables from a file - let's say config.php and you don't want a missing value to be replaced with a global defined somewhere else.
<?php
/**
* Filters out global vars from get_defined_vars() in order to get local vars only
* @param array $localVars pass get_defined_vars() here
*
* @return array local vars only
*/
function removeGlobals(array $localVars) {
return array_diff_key($localVars, $GLOBALS);
}
define('CONFIG_FILE_PATH', '/path/to/config.php');
function readConfig() {
require CONFIG_FILE_PATH;
$config = removeGlobals(get_defined_vars());
return $config;
}
?>
lbowerh at adelphia dot net ¶
20 years ago
Here is a function which generates a debug report for display or email
using get_defined_vars. Great for getting a detailed snapshot without
relying on user input.
<?php
function generateDebugReport($method,$defined_vars,$email="undefined"){
// Function to create a debug report to display or email.
// Usage: generateDebugReport(method,get_defined_vars(),email[optional]);
// Where method is "browser" or "email".
// Create an ignore list for keys returned by 'get_defined_vars'.
// For example, HTTP_POST_VARS, HTTP_GET_VARS and others are
// redundant (same as _POST, _GET)
// Also include vars you want ignored for security reasons - i.e. PHPSESSID.
$ignorelist=array("HTTP_POST_VARS","HTTP_GET_VARS",
"HTTP_COOKIE_VARS","HTTP_SERVER_VARS",
"HTTP_ENV_VARS","HTTP_SESSION_VARS",
"_ENV","PHPSESSID","SESS_DBUSER",
"SESS_DBPASS","HTTP_COOKIE");
$timestamp=date("m/d/y h:m:s");
$message="Debug report created $timestamp\n";
// Get the last SQL error for good measure, where $link is the resource identifier
// for mysql_connect. Comment out or modify for your database or abstraction setup.
global $link;
$sql_error=mysql_error($link);
if($sql_error){
$message.="\nMysql Messages:\n".mysql_error($link);
}
// End MySQL
// Could use a recursive function here. You get the idea ;-)
foreach($defined_vars as $key=>$val){
if(is_array($val) && !in_array($key,$ignorelist) && count($val) > 0){
$message.="\n$key array (key=value):\n";
foreach($val as $subkey=>$subval){
if(!in_array($subkey,$ignorelist) && !is_array($subval)){
$message.=$subkey." = ".$subval."\n";
}
elseif(!in_array($subkey,$ignorelist) && is_array($subval)){
foreach($subval as $subsubkey=>$subsubval){
if(!in_array($subsubkey,$ignorelist)){
$message.=$subsubkey." = ".$subsubval."\n";
}
}
}
}
}
elseif(!is_array($val) && !in_array($key,$ignorelist) && $val){
$message.="\nVariable ".$key." = ".$val."\n";
}
}
if($method=="browser"){
echo nl2br($message);
}
elseif($method=="email"){
if($email=="undefined"){
$email=$_SERVER["SERVER_ADMIN"];
}
$mresult=mail($email,"Debug Report for ".$_ENV["HOSTNAME"]."",$message);
if($mresult==1){
echo "Debug Report sent successfully.\n";
}
else{
echo "Failed to send Debug Report.\n";
}
}
}
?>
Joey ¶
6 years ago
I occasionally use this as a hack to convert arguments to an array where terseness is needed (dealing with legacy code, etc).
However in an object context it'll also pull in $this.
Make sure to unset it. If you map it to properties or an array then setting the key this wont be an error.
I recommend using a wrapper function that strips this from the result.
istiaquealamjoy at gmail dot com ¶
7 years ago
for all those who don't know how to us this function. copy and run this code in your computer .
note: you need to know what superglobals are.....
<?php
$A = 5 ;
$B = 10 ;
$C = 15 ;
$D = 20 ;
$F = get_defined_vars($A);
var_dump($F); //don't use echo. it will show error
?>
Result : will show all superglobals status along with your defined
variables along with its values
jgettys at gnuvox dot com ¶
22 years ago
Simple routine to convert a get_defined_vars object to XML.
<?php
function obj2xml($v, $indent='') {
while (list($key, $val) = each($v)) {
if ($key == '__attr') continue;
// Check for __attr
if (is_object($val->__attr)) {
while (list($key2, $val2) = each($val->__attr)) {
$attr .= " $key2=\"$val2\"";
}
}
else $attr = '';
if (is_array($val) || is_object($val)) {
print("$indent<$key$attr>\n");
obj2xml($val, $indent.' ');
print("$indent</$key>\n");
}
else print("$indent<$key$attr>$val</$key>\n");
}
}
//Example object
$x->name->first = "John";
$x->name->last = "Smith";
$x->arr['Fruit'] = 'Bannana';
$x->arr['Veg'] = 'Carrot';
$y->customer = $x;
$y->customer->__attr->id='176C4';
$z = get_defined_vars();
obj2xml($z['y']);
?>
will output:
<customer id="176C4">
<name>
<first>John</first>
<last>Smith</last>
</name>
<arr>
<Fruit>Bannana</Fruit>
<Veg>Carrot</Veg>
</arr>
</customer>
SyCo ¶
16 years ago
Here's a very simple function for debugging. It's far from perfect but I find it very handy. It outputs the var value and the var name on a new line. The problem is it'll echo any vars and their name if they share the same value. No big deal when debugging and saves the hassle of writing the HTML and var name when echoing a variable. (ev=echo variable). Using get_defined_vars() inside a function renames the var name to the functions variable so isn't as useful for debugging. Of course, you'll need access to the $GLOBALS array
<?
function ev($variable){
foreach($GLOBALS as $key => $value){
if($variable===$value){
echo '<p>'.$key.' - '.$value.'</p>';
}
}
}
$a=0;
ev($a);
$b=0;
ev($b);
$c=0;
ev($c);
?>
Will output
a - 0
a - 0
b - 0
a - 0
b - 0
c - 0
Joey ¶
6 years ago
I posted here before about "this" being in get_defined_vars.
It turns out it's not always there but in certain cases it will inexplicably appear.
php -r '
class Test {
public function a() {var_dump(array_keys(get_defined_vars()));$a = 123;}
public function b() {var_dump(array_keys(get_defined_vars()));$this;}
}
$t = new Test();
$t->a();
$t->b();
'
array()
array('this')
This does not happen in PHP 7.2 but will happen in PHP 5.6.
donovan at example dot com ¶
16 years ago
As a note, get_defined_vars() does not return a set of variable references (as I hoped). For example:
<?php
// define a variable
$my_var = "foo";
// get our list of defined variables
$defined_vars = get_defined_vars();
// now try to change the value through the returned array
$defined_vars["my_var"] = "bar";
echo $my_var, "\n";
?>
will output "foo" (the original value). It'd be nice if get_defined_vars() had an optional argument to make them references, but I imagine its a rather specialized request. You can do it yourself (less conveniently) with something like:
<?php
$defined_vars = array();
$var_names = array_keys(get_defined_vars());
foreach ($var_names as $var_name)
{
$defined_vars[$var_name] =& $$var_name;
}
?>
Joey ¶
6 years ago
Some comments here point out that this function wont return references. It does however return names and names are "references".
I would not recommend the suggestions here that convert it to references.
Instead...
public function x($a, $b, $c) {
foreach(array_keys(get_defined_vars()) as $key)
if($key !== 'this')
$this->y(${$key});
}
public function y(&$input) {
$input++;
}
Instead of ${} you can also use $$.
I have done some whacky things in my time to make extremely generic code but I've never had to do anything like the above. It might not even work (but should since it's no different to $a[$key]).
You could also do $$key++ but I've never seen code like that which wasn't horrifically bad (using dynamic where dynamic isn't beneficial).
If you're doing something like that then give it additional scrutiny.
Anonymous ¶
13 years ago
get_defined_vars() returns ALL the vars (in the current scope), what if you just want all YOUR vars, not PHP's super-globals?
<?php
var_export(array_diff(get_defined_vars(), array(array())));
?>
Example...
<?php
$TOP_LEVEL_VAR=1;
var_export(array_diff(get_defined_vars(), array(array())));
?>
The output (with register_globals off) should be...
array (
'TOP_LEVEL_VAR' => 1,
)
...it perfectly eliminated all the super-globals, without me having to specify them! (note with register_globals on, the output includes those globals, then TOP_LEVEL_VAR).
Here it is, as a function...(it's the best I could do {I can't call get_defined_vars() inside get_user_defined_vars() cuz of the scope issue}).
<?php
header('Content-type: text/plain');
$TOP_LEVEL_VAR=1;
echo 'register_globals(';
echo ini_get('register_globals');
echo ') '.phpversion()."\n";
var_export(get_user_defined_vars(get_defined_vars()));
function get_user_defined_vars($vars) {
return array_diff($vars, array(array()));
}
?>
Note that originally I had an array of the super-globals I wanted removed from get_defined_vars()'s array, then I noticed even an empty double-array, array(array()), made it give me the correct result. Weird.
This was tested on PHP 5.2.9.
Johan de Vries ¶
14 years ago
Note that this only returns things you've used. See http://bugs.php.net/bug.php?id=52110 . So don't expect this to have the $this entry, unless you assign $this to return $this.
meint at meint dot net ¶
13 years ago
Please be aware that function_get_vars only returns the variables defined at the point before you call the function_get_vars function, it does not scan the entire function for you, only the lines before you call it.
