for example:

<?php
$array = array('first'=>'111', 'second'=>'222', 'third'=>'333');print array_shift(array_keys($array));print array_pop(array_keys($array));print array_shift(array_values($array));print array_pop(array_values($array));
?>

Here's a way to find all the keys from a multidimensional array while keeping the array structure. An optional MAXIMUM DEPTH parameter can be set for testing purpose in case of very large arrays.

NOTE: If the sub element isn't an array, it will be ignore.

<?php
function array_keys_recursive($myArray, $MAXDEPTH = INF, $depth = 0, $arrayKeys = array()){
if($depth < $MAXDEPTH){
$depth++;
$keys = array_keys($myArray);
foreach($keys as $key){
if(is_array($myArray[$key])){
$arrayKeys[$key] = array_keys_recursive($myArray[$key], $MAXDEPTH, $depth);
}
}
}

return

<?php

$emptyArray

Want to traverse an multi dimensional array and get the keys back in a single dimensional array? This will do the trick:

<?phppublic function array_walk_keys($array, $parentKey = null, &$flattened_array = null)
{
if(!is_array($array))
return $array;

foreach(

if(

return

<?php
$array = array(
'e' => 'ieio'
,'1' => 'one'
,'2' => 'two'
,'0' => 'zero'
);
var_dump($array);
$keys = array_keys($array);
var_dump($keys);$string = '1e0';
for ($i = 0; $i < strlen($string); $i++) {
if (in_array($string[$i],$keys,'strict')) echo 'dude ';
else echo 'sweet ';
}
?>

array (size=4)

sweet dude sweet

----

Invalid:

Valid:

But Wait! Since PHP (currently) allows you to break a reference by wrapping a variable in parentheses, you can currently use:

echo array_shift( ( array_keys( array('a' => 'apple') ) ) );

However I would expect in time the PHP team will modify the rules of parentheses.

Guys in the array_keys function manual - https://www.php.net/manual/pt_BR/function.array-keys.php

it is described that in the second search parameter " $filter_value " is defined in mixed type, however in php 7.4 to version 8.1 when passing a $filter_value of type array, the function without returning false ( empty array )

Exemple :

$array = ['a' => 1, 'b' => 2];

var_dump(array_keys($array,array('a','b'))); // return array(0) { }

Debugging the code, I believe that the description of the $filter_value parameter is confusing, as it is understood that the value of the key in the array has to be the specified value and not the content of the key

<?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",""," ");
?>

how php sees this array: array("0"=>"0","1"=>"1","" =>"2"," "=>"3")

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 ;
}
?>

Regards

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

<?php

$query

This function will print all the keys of a multidimensional array in html tables.

<?php
function show_keys($ar){

echo

foreach (

echo

if (

echo

}

echo

}

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

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

<?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'));
?>

Array

[d] => what

Hope this helps someone.

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

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";
}
?>

<?php
function multiarray_keys($ar) {

foreach(

echo

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

foreach (

return

<?phpfunction array_extract($array, $extract_type = 1)
{
foreach ( $array as $key => $value )
{
if ( $extract_type == 1 && is_string($key) )
{
unset($array[$key]);
}
elseif ( $extract_type == 2 && is_int($key) )
{
unset($array[$key]);
}
}

return

<?php
$array = [
'element0',
'element1' => 'Hello World',
'element2' => 42,
'element3' => [ 'aaa', 'bbb' ],
];
print_r( array_keys($array) );
?>
is a surprising though correct

Arrays in php are really ordered key value pairs where if a value is missing it will become a value with a number as key. To get the intuitive first dimension of an array use a map with function to determine if a key is in fact an index.

<?php
$array_first = array_map(
fn ($key)=>
is_int($key)?$array[$key]:$key
,
array_keys($array)
);
print_r($array_first);
?>

Array

However in a niche case

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

function

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." ";
}
?>