Variable handling 函数
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get_defined_vars

(PHP 4 >= 4.0.4, PHP 5)

get_defined_vars — 返回由所有已定义变量所组成的数组

描述

array get_defined_vars ( void )

此函数返回一个包含所有已定义变量列表的多维数组，这些变量包括环境变量、服务器变量和用户定义的变量。

<?php
$b = array(1,1,2,3,5,8);

$arr = get_defined_vars();

// 打印 $b
print_r($arr["b"]);

// 打印 PHP 解释程序的路径（如果 PHP 作为 CGI 使用的话）
// 例如：/usr/local/bin/php
echo $arr["_"];

// 打印命令行参数（如果有的话）
print_r($arr["argv"]);

// 打印所有服务器变量
print_r($arr["_SERVER"]);

// 打印变量数组的所有可用键值
print_r(array_keys(get_defined_vars()));
?>

参见 get_defined_functions() 和 get_defined_constants()。

Variable handling 函数
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PHP手册
PHP手册 - N: 返回由所有已定义变量所组成的数组

用户评论:

Anonymous (18-Apr-2011 01:32)

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.

meint at meint dot net (11-Jan-2011 08:46)

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.

Johan de Vries (17-Jun-2010 04:09)

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.

donovan at example dot com (21-Oct-2008 05:15)

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;
}

?>

SyCo (21-Aug-2008 11:52)

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

kailashbadu at hotmail dot com (03-Mar-2007 11:09)

After a fruitless attempt find a built-in function whic did this, I wrote this functions to find out all the variables (well, those I wanted) in current scope and their values. I believe this is going to be handy in debugging.

<?php
  /**
   * @desc   works out the variables in the current scope(from where function was called).
   *         Returns an array with variable name as key and vaiable value as value
   * @param  $varList: variables returned by get_defined_vars() in desired scope.
   *         $excludeList: variables to be excluded from the list.
   * @return array
   */
  function getDefinedVars($varList, $excludeList)
  {
      $temp1 = array_values(array_diff(array_keys($varList), $excludeList));
      $temp2 = array();
      while (list($key, $value) = each($temp1)) {
          global $$value;
          $temp2[$value] = $$value;
      }
      return $temp2;
  }
 
  /**
   * @desc   holds the variable that are to be excluded from the list.
   *         Add or drop new elements as per your preference.
   * @var    array
   */
  $excludeList = array('GLOBALS', '_FILES', '_COOKIE', '_POST', '_GET', 'excludeList');
 
  //some dummy variables; add your own or include a file.
  $firstName = 'kailash';
  $lastName = 'Badu';
  $test = array('Pratistha', 'sanu', 'fuchhi');
 
  //get all variables defined in current scope
  $varList = get_defined_vars();
 
  //Time to call the function
  print "<pre>";
  print_r(getDefinedVars($varList, $excludeList));
  print "</pre>";
?>

zabmilenko at hotmail dot com (01-Sep-2006 03:32)

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.

lbowerh at adelphia dot net (05-Jun-2004 04:19)

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";     
      }
    }
}
?>

jgettys at gnuvox dot com (23-Feb-2002 03:09)

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>