array_key_exists
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
array_keys
(PHP 4, PHP 5)
array_keys — 배열의 모든 키를 반환
설명
array_keys()는 input 배열에서 숫자와 문자열의 키를 반환한다.
선택 인수 search_value 가 지정되면, 그 값에 대한 키만 반환한다. 그렇지 않으면, input 의 모든 키를 반환한다. PHP 5부터, strict 인수를 사용해서 자료형을 포함하여 비교(===)할 수 있습니다.
인수
- input
-
반환할 키를 가진 배열.
- search_value
-
지정하면, 이 값들을 가진 키만 반환합니다.
- strict
-
PHP 5부터, 이 인수는 검색 중에 엄격한 비교(===)를 하도록 합니다.
반환값
input 에 있는 모든 키의 배열을 반환합니다.
예제
Example #1 array_keys() 예제
<?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));
?>
위 예제의 출력:
Array
(
[0] => 0
[1] => color
)
Array
(
[0] => 0
[1] => 3
[2] => 4
)
Array
(
[0] => color
[1] => size
)
add a note
User Contributed Notes
array_keys
el dot quick at gmail dot com
24-Sep-2011 12:53
pat dot leblanc at gmail dot com
30-Aug-2011 06:35
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 12:08
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
24-Jan-2009 03:44
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
04-Dec-2008 06:05
<?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 04:40
<?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 10:16
/*
*
*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 11:13
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, $strict)));
}
?>
RQuadling at GMail dot com
28-Mar-2007 11:01
If you want to remove a value from an array, then there is no direct mechanism.
The following function uses the array_keys() function to find the key(s) of the value that you want to remove and then removes the elements for that key.
I've also given some examples and the output.
<?php
/**
* array array_remove ( array input, mixed search_value [, bool strict] )
**/
function array_remove(array &$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 $a_Input;
}
?>
Beside scalar variables (integers, floats, strings, boolean), you can also use arrays as the values you want to remove.
<?php
// Results in array(8, 8.0, '8', '8.0')
array_remove(array(8, 8.0, '8', '8.0', array(8), array('8')), array(8));
// Results in array(8, 8.0, '8', '8.0', array('8'))
array_remove(array(8, 8.0, '8', '8.0', array(8), array('8')), array(8), True);
?>
creator at mindcreations dot com
20-Mar-2007 08:42
This function will extract keys from a multidimensional array
<?php
function multiarray_keys($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($array));
echo "</pre>";
?>
Example output:
Array
(
[color] => Array
(
[1stcolor] => blue
[2ndcolor] => red
[3rdcolor] => green
)
[size] => Array
(
[0] => small
[1] => medium
[2] => large
)
)
Array
(
[0] => color
[1] => 1stcolor
[2] => 2ndcolor
[3] => 3rdcolor
[4] => size
[5] => 0
[6] => 1
[7] => 2
)
Ray.Paseur sometimes uses GMail
21-Dec-2006 11:08
Replace a key in an associative array, preserving the original order of keys and elements:
<?php
if (!function_exists('array_combine')) { // ONLY EXISTS IN PHP5
function array_combine($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 10:43
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)
20-Dec-2005 01:13
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 08:26
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
15-Aug-2005 01:50
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 07:16
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 $arr;
}
//}}}
} //endif function_exists
?>
webmaster [at] baz-x [dot] at
30-Jul-2005 08:13
I was looking for a function that deletes either integer keys or string keys (needed for my caching).
As I didn't find a function I came up with my own solution.
I didn't find the propiest function to post to so I will post it here, hope you find it useful.
<?php
function array_extract($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 $array;
}
?>
You can of course define constants to have a nicer look, I have chosen these: EXTR_INT = 1; EXTR_STRING = 2
EXTR_INT will return an array where keys are only integer while
EXTR_STRING will return an array where keys are only string
Have fun with it.
sip at email dot ee
22-Aug-2003 10:03
Note, that using array_key_exists() is rather inefficient. The overhead associated with calling a function makes it slower, than using isset($array[$key]), instead of array_key_exists($key, $array)
using isset() is usually about 1.3 times faster, according to my tests.
rodrigo at NOSPAM dot dhweb dot com dot br
05-Feb-2003 11:09
[Editor's note: For a complete solution to the printing of complex structures or hashes, see the PEAR::Var_Dump package: http://pear.php.net/package-info.php?pacid=103 , use "pear install Var_Dump" to get it]
This function will print all the keys of a multidimensional array in html tables.
It will help to debug when you dont have control of depths.
<?php
function show_keys($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
14-Nov-2002 04:15
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 10:33
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 03:35
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 )