数组 函数
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array_keys

(PHP 4, PHP 5)

array_keys — 返回数组中所有的键名

说明

array array_keys ( array $input [, mixed $search_value [, bool $strict ]] )

array_keys() 返回 input 数组中的数字或者字符串的键名。

如果指定了可选参数 search_value，则只返回该值的键名。否则 input 数组中的所有键名都会被返回。自 PHP 5 起，可以用 strict 参数来进行全等比较（===）。

Example #1 array_keys() 例子

<?php
$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));

$array = array("blue", "red", "green", "blue", "blue");
print_r(array_keys($array, "blue"));

$array = array("color" => array("blue", "red", "green"),
               "size"  => array("small", "medium", "large"));
print_r(array_keys($array));
?>

以上例程会输出：

Array
(
    [0] => 0
    [1] => color
)
Array
(
    [0] => 0
    [1] => 3
    [2] => 4
)
Array
(
    [0] => color
    [1] => size
)

参见 array_values() 和 array_key_exists()。

参数

input

An array containing keys to return.

search_value

If specified, then only keys containing these values are returned.

strict

Determines if strict comparison (===) should be used during the search.

返回值

Returns an array of all the keys in input.

更新日志

版本 说明
5.0.0 Added the strict parameter.

范例

Example #2 array_keys() example

<?php
$array = array(0 => 100, "color" => "red");
print_r(array_keys($array));

$array = array("blue", "red", "green", "blue", "blue");
print_r(array_keys($array, "blue"));

$array = array("color" => array("blue", "red", "green"),
               "size"  => array("small", "medium", "large"));
print_r(array_keys($array));
?>

以上例程会输出：

Array
(
    [0] => 0
    [1] => color
)
Array
(
    [0] => 0
    [1] => 3
    [2] => 4
)
Array
(
    [0] => color
    [1] => size
)

参见

数组 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 返回数组中所有的键名

用户评论:

anthony at berglas dot org (03-Apr-2012 01:32)

It should be noted that the inverse function to keys (which converts keys to values) is array_count_values (which converts values to keys).  This is needed to use things like array_intersect_key.  Could go in several places.  Took me a while to figure it out.

Na&#39;ven Enigma (10-Mar-2012 03:41)

I was trying to figure out how to normalize an array with numerical keys.  Since I was doing for() for a lot of things, but only replacing it if the conditions were right, I wound up with off ball arrays I couldn't access.  That being said, I looked for a method of normalizing the array and couldn't find one, so I built my own.  I'm not sure how to go about making it recursive, but I didn't need that feature for my own, so I just went without recursion.

//This will take array([5] => "test1", [4] => "test2", [9] => "test3") into array([0] => "test1", [1] => "test2", [2] => "test3") so you can access it easier.
        function normalize_array($array){
          $newarray = array();
          $array_keys = array_keys($array);
          $i=0;
          foreach($array_keys as $key){
           $newarray[$i] = $array[$key];
          
          $i++;
          }
          return $newarray;
        }

qeremy [atta] gmail [dotta] com (06-Mar-2012 01:50)

Simple ways to prefixing arrays;

<?php
function array_keys_prefix($arr, $pref = "") {
    $rarr = array();
    foreach ($arr as $key => $val) {
        $rarr[$pref.$key] = $val;
    }
    return $rarr;
}

function array_keys_prefix_multi($arr, $pref = "") {
    $rarr = array();
    foreach ($arr as $key => $val) {
        $rarr[] = array_keys_prefix($val, $pref);
    }
    return $rarr;
}

// $a = array("foo" => "FOO", "bar" => "BAR", "baz" => "BAZ"); // or
$a = array("foo" => "FOO", "bar" => "BAR", "baz" => array(1,2,3));
print_r(array_keys_prefix($a, "my_"));

// db fetch...
$products = array(
    array("id" => 1, "name" => "Foo"),
    array("id" => 2, "name" => "Bar")
);
print_r(array_keys_prefix_multi($products, "product_"));
?>

Array
(
    [my_foo] => FOO
    [my_bar] => BAR
    [my_baz] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

)
Array
(
    [0] => Array
        (
            [product_id] => 1
            [product_name] => Foo
        )

    [1] => Array
        (
            [product_id] => 2
            [product_name] => Bar
        )

)

izzecold at live dot de (10-Jan-2012 05:21)

<?php

/* A Function created by myself for checking multiple array keys
For Example u got an Array like $_SESSION and u wanna know if the keys 'user','pass','email' and 'type' exists.

*/

function mKeyChecker($arr,$keys=array()) {
    if(count($keys) > 1) {
        $valid_keys = 0;
        foreach($keys as $key) {
            if(array_key_exists($key,$arr)) $valid_keys++;
        }
        if($valid_keys == count($keys)) {
            return true;
        } else {
            return false;
        }
    } else if(count($keys) == 1) {
        if(array_key_exists($key[0],$arr)) {
            return true;
        } else {
            return false;
        }
    } else {
        return false;
    }
}

// Execution Example

if(mKeyChecker($_SESSION,array('id','user','email','type'))) {
    echo "is!";
} else {
    echo "not!";   
}

?>

craig1231 at hotmail dot com (22-Dec-2011 11:41)

A needed a function to find the keys which contain part of a string, not equalling a string...

<?php
function array_keys_contain($input, $search_value, $strict = false)
    {
        $tmpkeys = array();

        $keys = array_keys($input);

        foreach ($keys as $k)
        {
            if ($strict && strpos($k, $search_value) !== FALSE)
                $tmpkeys[] = $k;
            elseif (!$strict && stripos($k, $search_value) !== FALSE)
                $tmpkeys[] = $k;
        }

        return $tmpkeys;
    }
?>

el dot quick at gmail dot com (23-Sep-2011 04:23)

Sorry for my english...

I wrote a function to get keys of arrays recursivelly...

<?php
    function recursive_keys($input, $search_value = null){

        $output = ($search_value !== null ? array_keys($input, $search_value) : array_keys($input)) ;
        foreach($input as $sub){
            if(is_array($sub)){
                $output = ($search_value !== null ? array_merge($output, recursive_keys($sub, $search_value)) : array_merge($output, recursive_keys($sub))) ;
            }
        }
        return $output ;
    }
?>

I hope it will be usefull

Regards

pat dot leblanc at gmail dot com (29-Aug-2011 10:05)

It's worth noting that if you have keys that are long integer, such as '329462291595', they will be considered as such on a 64bits system, but will be of type string on a 32 bits system.

for example:
<?php

$importantKeys = array('329462291595' =>null, 'ZZ291595' => null);

foreach(array_keys($importantKeys) as $key){
    echo gettype($key)."\n";
}

?>

will return on a 64 bits system:
<?php
    integer
    string
?>

but on a 32 bits system:
<?php
    string
    string
?>

I hope it will save someone the huge headache I had :)

rarioj at gmail dot com (05-Oct-2009 02:38)

Sometimes we want to find out the last added numerical key right after we use " array_push($array, $value) " or " $array[] = $value ". This can be achieved by calling:

<?php
return array_pop(array_keys($array));
?>

ferrerna at gmail dot com (23-Jan-2009 05:14)

Here's a function I needed to collapse an array, in my case from a database query.  It takes an array that contains key-value pairs and returns an array where they are actually the key and value.

<?php

function array_collapse($arr, $x, $y) {
    $carr = array();
    while ($el = current($arr)) {
        $carr[ $el[$x] ] = $el[$y];
        next($arr);
    }
    return $carr;
}

?>

Example usage (pseudo-database code):

<?php

$query = db_query('SELECT name, value FROM properties');

$result = db_returnAll($query);

/* This will return an array like so:

[
   ['name' -> 'color', 'value' -> 'blue'],
   ['name' -> 'style', 'value' -> 'wide-format'],
   ['name' -> 'weight', 'value' -> 3.6],
   ['name' -> 'name', 'value' -> 'Waerdthing']
]

*/

$propArr = array_collapse($result, 'name', 'value');

/* Now this array looks like:

[
   ['color' -> 'blue'],
   ['style' -> 'wide-format'],
   ['weight' -> 3.6],
   ['name' -> 'Waerdthing'],

*/

?>

I found this handy for using with json_encode and am using it for my project http://squidby.com

nodarinodo at mail dot ru (03-Dec-2008 07:35)

<?php
    //It's a way to get keys from values )
    $es = array("is My FullName"=>"nodar chkuaselidze (nodarinodo)", "You Are" => "I don't know", "Is My Friend" => "ruxadze");
    foreach(array_values($es) as $ess){
        echo $ess." =>";
           
    for($i =0; $i < count(array_keys($es, $ess)); $i++){
            echo reset(array_keys($es, $ess))."<BR>";
        } }
?>

neil at 11 out of 10 (24-Jul-2008 08:10)

<?php

/*
 * This function will return the keys of elements in the
 * haystack where the value is found in array needle
 */

function array_value_intersect_keys( $array_haystack, $array_needle ){
    $intersected = array_intersect( $array_haystack, $array_needle );
    return array_keys( $intersected );
}

// usage

$array_haystack = array( 1 => 2, 2 => 5, 'red' => 8, 9 => 14 );

$array_needle = array( 2, 8 );

$array_keys_of_intersecting_values = array_value_intersect_keys( $array_haystack, $array_needle );

print_r( $array_keys_of_intersecting_values );
?>

returns
Array
(
    [0] => 1
    [1] => red
)

edsongarrido at gmail dot com (12-Jun-2008 01:46)

/*
*
*This function will return a .csv from a given array inside the $_SESSION['my_array']
*
*$csv_name -> the name we want the csv has to
*$download -> true or false to download the csv file after done
*
*/

<?php

function createCSV($csv_name, $download) {

        $i = 1;
        $csv = "";

        /* erase the old file, if it exists */
        @unlink("../../csv/" . $csv_name . ".csv");

        /* array is in a session variable
         * this may be useful to avoid many db queries if it is the case */
        $my_array = $_SESSION['my_array'];

        /* how many fields has the given array */
        $fields = count(array_keys($my_array[0]));

        /* extracting the titles from the array */
        foreach(array_keys($my_array[0]) as $title)
        {
            /* array_keys percurs the title of each vector */
            $csv .= $title;

            /* while it is not the last field put a semi-colon ; */
            if($i < $fields)
                $csv .= ";";

            $i++;
        }

        /* insert an empty line to better visualize the csv */
        $csv .= chr(10).chr(13);
                $csv .= chr(10).chr(13);

        /* get the values from the extracted keys */
        foreach (array_keys($my_array) as $tipo)
        {

            $i = 1;

            foreach(array_keys($my_array[$tipo]) as $sub)
            {

                $csv .= $my_array[$tipo][$sub];

                if ($i < $fields)
                    $csv .= ";";

                $i++;
            }

            $csv .= chr(10).chr(13);

        }

        /* export the csv */
        $export_csv=fopen("../../csv/". $csv_name .".csv", "w+");
        fwrite($export_csv, $csv);
        fclose($export_csv);

        /* download the csv */
        if ($download == true)
            header('Location:' . "../../csv/" . $csv_name . ".csv");

        exit();

    }

?>

Hayley Watson (05-Oct-2007 02:43)

An alternative to RQuadling at GMail dot com's array_remove() function:

<?php
function array_remove(array $array, $value, $strict=false)
{
    return array_diff_key($array, array_flip(array_keys($array, $value, $strict)));
}
?>

RQuadling at GMail dot com (28-Mar-2007 01:31)

If you want to remove a value from an array, then there is no direct mechanism.

The following function uses the array_keys() function to find the key(s) of the value that you want to remove and then removes the elements for that key.

I've also given some examples and the output.

<?php
/**
  * array array_remove ( array input, mixed search_value [, bool strict] )
  **/
function array_remove(array &$a_Input, $m_SearchValue, $b_Strict = False) {
    $a_Keys = array_keys($a_Input, $m_SearchValue, $b_Strict);
    foreach($a_Keys as $s_Key) {
        unset($a_Input[$s_Key]);
    }
    return $a_Input;
}
?>

Beside scalar variables (integers, floats, strings, boolean), you can also use arrays as the values you want to remove.

<?php
// Results in array(8, 8.0, '8', '8.0')
array_remove(array(8, 8.0, '8', '8.0', array(8), array('8')), array(8));

// Results in array(8, 8.0, '8', '8.0', array('8'))
array_remove(array(8, 8.0, '8', '8.0', array(8), array('8')), array(8), True);
?>

creator at mindcreations dot com (20-Mar-2007 10:12)

This function will extract keys from a multidimensional array

<?php
function multiarray_keys($ar) {
           
    foreach($ar as $k => $v) {
        $keys[] = $k;
        if (is_array($ar[$k]))
            $keys = array_merge($keys, multiarray_keys($ar[$k]));
    }
    return $keys;
}
?>

Example code:

<?php
$array = array("color" => array("1stcolor" => "blue", "2ndcolor" => "red", "3rdcolor" => "green"),
               "size"  => array("small", "medium", "large"));

echo "<pre>";
print_r($array);
echo "</pre>";

echo "<pre>";
print_r(multiarray_keys($array));
echo "</pre>";
?>

Example output:

Array
(
    [color] => Array
        (
            [1stcolor] => blue
            [2ndcolor] => red
            [3rdcolor] => green
        )

    [size] => Array
        (
            [0] => small
            [1] => medium
            [2] => large
        )

)

Array
(
    [0] => color
    [1] => 1stcolor
    [2] => 2ndcolor
    [3] => 3rdcolor
    [4] => size
    [5] => 0
    [6] => 1
    [7] => 2
)

Ray.Paseur sometimes uses GMail (21-Dec-2006 12:38)

Replace a key in an associative array, preserving the original order of keys and elements:

<?php
if (!function_exists('array_combine')) { // ONLY EXISTS IN PHP5
    function array_combine($keys, $values) {
        if (count($keys) != count($values)) {
    return false; }
        foreach($keys as $key) { $array[$key] = array_shift($values); }
    return $array; }   
} // END IF FUNCTION EXISTS

$keys = array_keys($array);
$values = array_values($array);
foreach ($keys as $k => $v) {
    if ($v == "MANAGEMENT FEE CHARGE") { $keys[$k] = "MANAGEMENT FEES"; }
}
$array = array_combine($keys, $values);
?>

jochem (18-Feb-2006 12:13)

might be worth noting in the docs that not all associative (string) keys are a like, output of the follow bit of code demonstrates - might be a handy introduction to automatic typecasting in php for some people (and save a few headaches):

<?php
$r = array("0"=>"0","1"=>"1","" =>"2"," "=>"3");
echo 'how php sees this array: array("0"=>"0","1"=>"1","" =>"2"," "=>"3")',"\n-----------\n";
var_dump($r); print_r($r); var_export($r);
echo "\n-----------\n",'var_dump("0","1",""," ") = ',"\n-----------\n";
var_dump("0","1",""," ");
?>

OUTPUTS:

how php sees this array: array("0"=>"0","1"=>"1","" =>"2"," "=>"3")
-----------
array(4) {
  [0]=>
  string(1) "0"
  [1]=>
  string(1) "1"
  [""]=>
  string(1) "2"
  [" "]=>
  string(1) "3"
}
Array
(
    [0] => 0
    [1] => 1
    [] => 2
    [ ] => 3
)
array (
  0 => '0',
  1 => '1',
  '' => '2',
  ' ' => '3',
)
-----------
var_dump("0","1",""," ") =
-----------
string(1) "0"
string(1) "1"
string(0) ""
string(1) " "

Sven (bitcetera.com) (19-Dec-2005 02:43)

Here's how to get the first key, the last key, the first value or the last value of a (hash) array without explicitly copying nor altering the original array:

<?php
  $array = array('first'=>'111', 'second'=>'222', 'third'=>'333');

  // get the first key: returns 'first'
  print array_shift(array_keys($array));

  // get the last key: returns 'third'
  print array_pop(array_keys($array));

  // get the first value: returns '111'
  print array_shift(array_values($array));

  // get the last value: returns '333'
  print array_pop(array_values($array));
?>

vesely at tana dot it (09-Dec-2005 09:56)

The position of an element.

One can apply array_keys twice to get the position of an element from its key. (This is the reverse of the function by cristianDOTzuddas.) E.g., the following may output "yes, we have bananas at position 0".

<?php
$a = array("banana" => "yellow", "apple" = "red");
$k = get_some_fruit();
if (isset($a[$k]))
{
   list($pos) = array_keys(array_keys($a), $k);
   print "yes, we have {$k}s at position $pos\n";
}
?>

Not amazingly efficient, but I see no better alternative.

ru dot dy at gmx dot net (14-Aug-2005 05:20)

I was looking for a function that simply unset a variable amout of values from a one-dimensional array by key. I ended up with this (returns the array itself if no further parameter than the array is given, false with no params - does not change the source array)

usage: array_remove(array $input [, mixed key ...])

<?php

  function array_remove() {
    if ($stack = func_get_args()) {
      $input = array_shift($stack);
      foreach ($stack as $key) {
        unset($input[$key]);
      }
      return $input;
    }
    return false;
  }

?>

Test:

<?php
  $a = array('a'=>'fun', 'b'=>3.14, 'sub'=> array('1', '2', '3'), 'd'=>'what', 'e' => 'xample', 5 => 'x');
  print_r($a);
  print_r(array_remove($a, 'd', 'b', 5, 'sub'));
?>

Output:

Array
(
    [a] => fun
    [b] => 3.14
    [sub] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
        )

    [d] => what
    [e] => xample
    [5] => x
)
Array
(
    [a] => fun
    [e] => xample
)

Hope this helps someone.

alex [@T] d-sn [D@T] com / Alex Galisteo (07-Aug-2005 10:46)

My version of PHP does not support the strict parameter. Moreover, I need a function that could make other comparsion different than equals and stricktly equals.

The funcition array_keys_advanced can make the following comparsions: equal, not equal, strictly greater than, equal or greater than, strictly less than, equal or less than.

<?php
if (!function_exists('array_keys_advanced')) {
    //{{{ array_keys_advanced
    /**
     * Returns an array with the matching keys as values. A comparsion type can
     * be spcified, even if it should be a strict comparsion or not.
     * Note: It is not recursive.
     *
     * @param    array    $input
     * @param    string   $search_value
     * @param    bool     $strict
     * @param    string   $comparison: {EQ | NEQ | GT | EGT | LT | ELT}
     * @return   Returns an array with the matching keys as values.
     * @author   alex [@T] d-sn [D@T] com // Alex Galisteo
     */
    function array_keys_advanced() {
        $nargs = func_num_args();
        $arr = array();
        $input = null;
        $search_value = null;
        $strict = (bool) false;
        $comparison  = "EQ";
        $comparsion_types = array("EQ", "NEQ", "GT", "EGT", "LT", "ELT");
        switch ($nargs) {
        case 1:
            $input = func_get_arg(0);
            return array_keys($input);
            break;
        case 2:
            $input = func_get_arg(0);
            $search_value = func_get_arg(1);
            return array_keys($input, $search_value);
            break;
        case 3:
            $input = func_get_arg(0);
            $search_value = func_get_arg(1);
            $strict = (bool) func_get_arg(2);
            $comparsion  = "EQ";
            break;
        case 4:
            $input = func_get_arg(0);
            $search_value = func_get_arg(1);
            $strict = (bool) func_get_arg(2);
            $comparsion = strtoupper((string) func_get_arg(3));
            $comparsion = (in_array($comparsion, $comparsion_types))?
                            $comparsion : "EQ";
            break;
        default:
            return $arr;
            break;
        }
        foreach ($input as $key => $val) {
            if ($strict) {
                if ($comparsion == "EQ" && $search_value === $val) {
                    $arr[] = $key;
                }
                elseif ($comparsion == "NEQ" && $search_value !== $val)
                    $arr[] = $key;
                elseif ($comparsion == "GT" && $search_value > $val)
                    $arr[] = $key;
                elseif ($comparsion == "EGT" && $search_value >= $val)
                    $arr[] = $key;
                elseif ($comparsion == "LT" && $search_value < $val)
                    $arr[] = $key;
                elseif ($comparsion == "ELT" && $search_value <= $val)
                    $arr[] = $key;
            } else {
                if ($comparsion == "EQ" && $search_value == $val)
                    $arr[] = $key;
                elseif ($comparsion == "NEQ" && $search_value != $val)
                    $arr[] = $key;
                elseif ($comparsion == "GT" && $search_value > $val)
                    $arr[] = $key;
                elseif ($comparsion == "EGT" && $search_value >= $val)
                    $arr[] = $key;
                elseif ($comparsion == "LT" && $search_value < $val)
                    $arr[] = $key;
                elseif ($comparsion == "ELT" && $search_value <= $val)
                    $arr[] = $key;
            }
        }
        return $arr;
    }
    //}}}
} //endif function_exists
?>

webmaster [at] baz-x [dot] at (29-Jul-2005 11:43)

I was looking for a function that deletes either integer keys or string keys (needed for my caching).
As I didn't find a function I came up with my own solution.
I didn't find the propiest function to post to so I will post it here, hope you find it useful.

<?php

function array_extract($array, $extract_type = 1)
{
    foreach ( $array as $key => $value )
    {
        if ( $extract_type == 1 && is_string($key) )
        {
            // delete string keys
            unset($array[$key]);
        }
        elseif ( $extract_type == 2 && is_int($key) )
        {
            // delete integer keys
            unset($array[$key]);
        }
    }

    return $array;
}

?>

You can of course define constants to have a nicer look, I have chosen these: EXTR_INT = 1; EXTR_STRING = 2
EXTR_INT will return an array where keys are only integer while
EXTR_STRING will return an array where keys are only string

Have fun with it.

sip at email dot ee (22-Aug-2003 01:33)

Note, that using array_key_exists() is rather inefficient. The overhead associated with calling a function makes it slower, than using isset($array[$key]), instead of array_key_exists($key, $array)
using isset() is usually about 1.3 times faster, according to my tests.

rodrigo at NOSPAM dot dhweb dot com dot br (05-Feb-2003 12:39)

[Editor's note: For a complete solution to the printing of complex structures or hashes, see the PEAR::Var_Dump package: http://pear.php.net/package-info.php?pacid=103 , use "pear install Var_Dump" to get it]

This function will print all the keys of a multidimensional array in html tables.
It will help to debug when you dont have control of depths.

<?php
function show_keys($ar){

   echo "<table width='100%' border='1' bordercolor='#6699CC' cellspacing='0' cellpadding='5'><tr valign='top'>";

      foreach ($ar as $k => $v ) {

         echo "<td align='center' bgcolor='#EEEEEE'>
           <table border='2' cellpadding='3'><tr><td bgcolor='#FFFFFF'><font face='verdana' size='1'>
              " . $k . "
           </font></td></tr></table>";

           if (is_array($ar[$k])) {
              show_keys ($ar[$k]);
         }

         echo "</td>";

      }

   echo "</tr></table>";

}

// Multidimensional array ->
$arvore = array();
$arvore['1'] = array();
$arvore['1']['1.1'] = array('1.1.1', '1.1.2', '1.1.3');
$arvore['1']['1.2'] = array('1.2.1', '1.2.2', '1.2.3');
$arvore['1']['1.3'] = array('1.3.1', '1.3.2', '1.3.3');
$arvore['2'] = array();
$arvore['2']['2.1'] = array('2.1.1', '2.1.2', '2.1.3');
$arvore['2']['2.2'] = array('2.2.1', '2.2.2', '2.2.3');
$arvore['2']['2.3'] = array('2.3.1', '2.3.2', '2.3.3');
$arvore['3'] = array();
$arvore['3']['3.1'] = array('3.1.1', '3.1.2', '3.1.3');
$arvore['3']['3.2'] = array('3.2.1', '3.2.2', '3.2.3');
$arvore['3']['3.3'] = array('3.3.1', '3.3.2'=>array('3.3.2.1', '3.3.2.2'), '3.3.3');
// <-

show_keys($arvore);
?>

michielbakker at msn dot com (13-Nov-2002 05:45)

If you receive a bunch of variables and like to change most of them (or all of them for that matter), you can do something like this: (data has been sent to a page with POST)

<?php
$allKeys = array_keys($HTTP_POST_VARS);

for ($i=0;$i<count($allKeys);$i++)
{
      $$allKeys[$i] = strtoupper($HTTP_POST_VARS[$allKeys[$i]]);
}
?>

This makes caracters (a-z) uppercase. This is just one way to use it, ofcourse.

Hope this helps someone understand the way to use array_keys() or give any ideas. :)

glennh at webadept dot net (13-Nov-2002 12:03)

All the cool notes are gone from the site.

Here's an example of how to get all the variables passed to your program using the method on this page. This prints them out so you can see what you are doing.

<?php
while (list($key, $value) = each
(${"HTTP_".$REQUEST_METHOD."_VARS"}))
{
        echo $key." = ".$value." ";
}
?>

jacob at keystreams dot com (21-Aug-2002 07:05)

Here is a way to use array_intersect on array keys rather than values:

<?php
$a = array("apple" => "red", "banana" => "yellow");
$z = array("apple" => "green", "peach" => "orange", "banana" => "rotten");

$intersected_keys = array_intersect(array_keys($a), array_keys($z));

print_r($intersected_keys);
?>

This will print:

Array ( [0] => apple [1] => banana )