array_change_key_case

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

array_change_key_caseChanges the case of all keys in an array

Description

array_change_key_case(array $array, int $case = CASE_LOWER): array

Returns an array with all keys from array lowercased or uppercased. Numbered indices are left as is.

Parameters

array

The array to work on

case

Either CASE_UPPER or CASE_LOWER (default)

Return Values

Returns an array with its keys lower or uppercased.

Examples

Example #1 array_change_key_case() example

<?php
$input_array
= array("FirSt" => 1, "SecOnd" => 4);
print_r(array_change_key_case($input_array, CASE_UPPER));
?>

The above example will output:

Array
(
    [FIRST] => 1
    [SECOND] => 4
)

Notes

Note:

If an array has indices that will be the same once run through this function (e.g. "keY" and "kEY"), the value that is later in the array will override other indices.

add a note

User Contributed Notes 20 notes

up
23
qeremy [atta] gmail [dotta] com
12 years ago
Unicode example;

<?php
function array_change_key_case_unicode($arr, $c = CASE_LOWER) {
$c = ($c == CASE_LOWER) ? MB_CASE_LOWER : MB_CASE_UPPER;
foreach (
$arr as $k => $v) {
$ret[mb_convert_case($k, $c, "UTF-8")] = $v;
}
return
$ret;
}

$arr = array("FirSt" => 1, "yağ" => "Oil", "şekER" => "sugar");
print_r(array_change_key_case($arr, CASE_UPPER));
print_r(array_change_key_case_unicode($arr, CASE_UPPER));
?>

Array
(
[FIRST] => 1
[YAğ] => Oil
[şEKER] => sugar
)
Array
(
[FIRST] => 1
[YAĞ] => Oil
[ŞEKER] => sugar
)
up
10
zhangxuejiang
4 years ago
I improve the array_change_key_case_recursive function ,let it can lowercase or uppercase keys

function array_change_key_case_recursive($arr, $case = CASE_LOWER)
{
return array_map(function($item) use($case) {
if(is_array($item))
$item = array_change_key_case_recursive($item, $case);
return $item;
},array_change_key_case($arr, $case));
}
up
11
xsaero00
10 years ago
Here is the most compact way to lower case keys in a multidimensional array

function array_change_key_case_recursive($arr)
{
return array_map(function($item){
if(is_array($item))
$item = array_change_key_case_recursive($item);
return $item;
},array_change_key_case($arr));
}
up
2
msegit post pl
3 years ago
Improved multidimensional unicode func (after qeremy):
<?php
function array_change_key_case_unicode_recurs($arr, $c = CASE_LOWER) {
foreach (
$arr as $k => $v) {
$ret[mb_convert_case($k, (($c === CASE_LOWER) ? MB_CASE_LOWER : MB_CASE_UPPER), "UTF-8")] = (is_array($v) ? array_change_key_case_unicode_recurs($v, $c) : $v );
}
return
$ret;
}

$arr = array("FirSt" => 1, "ZażóŁć gęŚlą jaŹń" => array("yağ" => "Oil", "şekER" => "sugar") );
print_r(array_change_key_case($arr, CASE_UPPER));
print_r(array_change_key_case_unicode_recurs($arr, CASE_UPPER));
?>

Array
(
[FIRST] => 1
[ZAżóŁć GęŚLą JAŹń] => Array
(
[yağ] => Oil
[şekER] => sugar
)
)
Array
(
[FIRST] => 1
[ZAŻÓŁĆ GĘŚLĄ JAŹŃ] => Array
(
[YAĞ] => Oil
[ŞEKER] => sugar
)
)
up
-1
gsoft
11 months ago
//Array key case change recursively (Unicode):

<?php
function array_key_case($data,$case=FALSE)
{
$ret=array();
if (
is_array($data) )
foreach (
$data as $idx => $val)
$ret[$case ? mb_strtoupper($idx) : mb_strtolower($idx)]=array_key_case($val,$case);
else
$ret=$data;
return
$ret;
}
up
-1
shaman_master at list dot ru
4 years ago
<?php
/**
* Convert keys in an array.
*
* @param array $array Source data
* @param callable $callback Function name (strtolower, strtoupper, ucfirst, lcfirst, ucwords)
* @return array
*/
function array_convert_key_case(array $array, callable $callback = 'strtolower')
{
return
array_combine(
array_map($callback, array_keys($array)),
array_values($array)
);
}
?>
up
0
andreas dot schuhmacher87 at googlemail dot com
16 years ago
multibyte and multi-dimensional-array support, have fun!

<?php
define
('ARRAY_KEY_FC_LOWERCASE', 25); //FOO => fOO
define('ARRAY_KEY_FC_UPPERCASE', 20); //foo => Foo
define('ARRAY_KEY_UPPERCASE', 15); //foo => FOO
define('ARRAY_KEY_LOWERCASE', 10); //FOO => foo
define('ARRAY_KEY_USE_MULTIBYTE', true); //use mutlibyte functions

/**
* change the case of array-keys
*
* use: array_change_key_case_ext(array('foo' => 1, 'bar' => 2), ARRAY_KEY_UPPERCASE);
* result: array('FOO' => 1, 'BAR' => 2)
*
* @param array
* @param int
* @return array
*/
function array_change_key_case_ext(array $array, $case = 10, $useMB = false, $mbEnc = 'UTF-8') {
$newArray = array();

//for more speed define the runtime created functions in the global namespace

//get function
if($useMB === false) {
$function = 'strToUpper'; //default
switch($case) {
//first-char-to-lowercase
case 25:
//maybee lcfirst is not callable
if(!function_exists('lcfirst'))
$function = create_function('$input', '
return strToLower($input[0]) . substr($input, 1, (strLen($input) - 1));
'
);
else
$function = 'lcfirst';
break;

//first-char-to-uppercase
case 20:
$function = 'ucfirst';
break;

//lowercase
case 10:
$function = 'strToLower';
}
} else {
//create functions for multibyte support
switch($case) {
//first-char-to-lowercase
case 25:
$function = create_function('$input', '
return mb_strToLower(mb_substr($input, 0, 1, \''
. $mbEnc . '\')) .
mb_substr($input, 1, (mb_strlen($input, \''
. $mbEnc . '\') - 1), \'' . $mbEnc . '\');
'
);

break;

//first-char-to-uppercase
case 20:
$function = create_function('$input', '
return mb_strToUpper(mb_substr($input, 0, 1, \''
. $mbEnc . '\')) .
mb_substr($input, 1, (mb_strlen($input, \''
. $mbEnc . '\') - 1), \'' . $mbEnc . '\');
'
);

break;

//uppercase
case 15:
$function = create_function('$input', '
return mb_strToUpper($input, \''
. $mbEnc . '\');
'
);
break;

//lowercase
default: //case 10:
$function = create_function('$input', '
return mb_strToLower($input, \''
. $mbEnc . '\');
'
);
}
}

//loop array
foreach($array as $key => $value) {
if(
is_array($value)) //$value is an array, handle keys too
$newArray[$function($key)] = array_change_key_case_ex($value, $case, $useMB);
elseif(
is_string($key))
$newArray[$function($key)] = $value;
else
$newArray[$key] = $value; //$key is not a string
} //end loop

return $newArray;
}
?>
up
-2
NetPanther
11 years ago
Use this to capitalize first letter of all array keys:

<?php

function ucfirstKeys(&$data)
{
foreach (
$data as $key => $value)
{
// Convert key
$newKey = ucfirst($key);

// Change key if needed
if ($newKey != $key)
{
unset(
$data[$key]);
$data[$newKey] = $value;
}

// Handle nested arrays
if (is_array($value))
{
ucfirstKeys($data[$key]);
}
}
}

$test = array('foo' => 'bar', 'moreFoo' => array('more' => 'foo'));
ucfirstKeys($test);
print_r($test);

?>

Result:
Array ( [MoreFoo] => Array ( [More] => foo ) [Foo] => bar )
up
-5
Lus Henrique Pessoa
13 years ago
<?php

// improving the previous script
function ack_r3(&$array, $case=CASE_LOWER, $flag_rec=false)
{
$array = array_change_key_case($array, $case);
if (
$flag_rec ) {
foreach (
$array as $key => $value) {
if (
is_array($value) ) {
ack_r3($array[$key], $case, true);
}
}
}
}

// same of array_change_key_case
$arr = array('ID' => 1, 'NAME'=> 'Luis', 'Contact' => array('PHONE' => '3010-7148', 'E-MAIL' => 'luis@net.com') );
ack_r3($arr, CASE_LOWER,false);
var_dump($arr);

$arr = array('ID' => 1, 'NAME'=> 'Luis', 'Contact' => array('PHONE' => '3010-7148', 'E-MAIL' => 'luis@net.com') );
ack_r3($arr, CASE_LOWER,true);
var_dump($arr);

?>

outputs:

array(3) {
["id"]=>
int(1)
["name"]=>
string(4) "Luis"
["contact"]=>
array(2) {
["PHONE"]=>
string(9) "3010-7148"
["E-MAIL"]=>
string(12) "luis@net.com"
}
}
array(3) {
["id"]=>
int(1)
["name"]=>
string(4) "Luis"
["contact"]=>
array(2) {
["phone"]=>
string(9) "3010-7148"
["e-mail"]=>
string(12) "luis@net.com"
}
}
up
-4
anon at ymous dot com
15 years ago
Below is a recursive version of this function.

<?php
/**
* A recursive array_change_key_case function.
* @param array $input
* @param integer $case
*/
function array_change_key_case_recursive($input, $case = null){
if(!
is_array($input)){
trigger_error("Invalid input array '{$array}'",E_USER_NOTICE); exit;
}
// CASE_UPPER|CASE_LOWER
if(null === $case){
$case = CASE_LOWER;
}
if(!
in_array($case, array(CASE_UPPER, CASE_LOWER))){
trigger_error("Case parameter '{$case}' is invalid.", E_USER_NOTICE); exit;
}
$input = array_change_key_case($input, $case);
foreach(
$input as $key=>$array){
if(
is_array($array)){
$input[$key] = array_change_key_case_recursive($array, $case);
}
}
return
$input;
}
?>
up
-5
Luis Henrique Pessoa
13 years ago
Script to change case of sub-arrays keys:

<?php

function arrKey2Lower(&$arrVals) {
foreach(
$arrVals as $key => $item ) {
$key2 = strtolower($key);
if (
$key2 != $key) {
unset(
$arrVals[$key]);
$arrVals[$key2]=$item;
$key=$key2;
}

if (
is_array($item) ) { arrKey2Lower($arrValores[$key]); }
}
}

$arr = array('ID' => 1, 'NAME'=> 'Luis', 'Contact' => array('PHONE' => '3010-7148', 'E-MAIL' => 'luis@net.com') );
arrKey2Lower($arr);
var_dump($arr);


?>

outputs:

array(3) {
["id"]=>
int(1)
["name"]=>
string(4) "Luis"
["contact"]=>
array(2) {
["phone"]=>
string(9) "3010-7148"
["e-mail"]=>
string(12) "luis@net.com"
}
}
up
-5
john at doe dot com
16 years ago
<?php
function array_change_value_case($input, $case = CASE_LOWER)
{
$aRet = array();

if (!
is_array($input))
{
return
$aRet;
}

foreach (
$input as $key => $value)
{
if (
is_array($value))
{
$aRet[$key] = array_change_value_case($value, $case);
continue;
}

$aRet[$key] = ($case == CASE_UPPER ? strtoupper($value) : strtolower($value));
}

return
$aRet;
}
?>
up
-4
cm at gameswelt dot de
16 years ago
I just changed the code a little bit so you havent got a code that repeats itself.

<?php

function array_change_key_case_secure($array = array(), $case = CASE_UPPER){
$secure = array();
$functionWrap = array(CASE_UPPER => 'strtoupper',
CASE_LOWER => 'strtolower');

foreach(
$array as $key => $val){
if(isset(
$functionWrap[$key])){
$key = $functionWrap[$case]($key);
$secure[$key][] = $val;
} else {
die(
'Not a known Type');
}
}

foreach(
$secure as $key => $val){
if(
count($secure[$key]) == 1){
$secure[$key] = $val[0];
}
}

return
$secure;
}

$myArray = array('A' => 'Hello',
'B' => 'World',
'a' => 'how are you?');

print_r($myArray);
$myArray = array_change_key_case_secure($myArray);
print_r($myArray);

/*
Array
(
[A] => Hello
[B] => World
[a] => how are you?
)
Array
(
[A] => Array
(
[0] => Hello
[1] => how are you?
)

[B] => World
)
*/
up
-7
JOE
12 years ago
Script to change case of sub-arrays keys to lower . It works well for me. hope it helps.

<?php
$array
=array("First"=>"val1","SecoNd"=>"val2",
"third"=>array("third-INner1"=>"val3.1"),
"fourth"=>array("FouthINNer1"=>"val4.1","FourthINNER2"=>"val4.2"));
print_r($array);
$key=array_keys($array);
foreach(
$key as $ki)
{
$klower=strtolower($ki);
$val=$array[$ki];
if(
is_array($val))
{
foreach(
$val as $kinner=>$vinner)
{

$tl=strtolower($kinner);
unset(
$val[$kinner]);
$val[$tl]=$vinner;
}
}
unset(
$array[$ki]);
$array[$klower]=$val;
}
echo
"<br> After Changing Key to-LowerCase : <br>";
print_r($array);

?>
up
-6
oulala at yandex dot com
8 years ago
Recursive LowerCase First Letter in array key

if(!function_exists("mb_lcfirstKeys")) {
function mb_lcfirstKeys($data) {
$res = [];
foreach ($data as $key => $value) {
$newKey = mb_lcfirst($key);
$res[$newKey] = is_array($value) ? mb_lcfirstKeys($value) : $value;
}
return $res;
}
}
up
-2
wendri dot net at gmail dot com
1 year ago
Array of partitions with always the same number of sub-array indexes.

<?php

function partitionFixedSubArray($array, $length, $empty_space)
{
$result = [];

if (
sizeof($array) ) {

$result = array_chunk($array, $length);
$last_array_count = sizeof(end($result));

if (
$last_array_count < $length) {

for (
$i = $last_array_count; $i < $length; $i++) {
array_push($result[key($result)], $empty_space);
}
}
}

return
$result;
}

$employees = [
"Paidi",
"Paijo",
"Darno",
"Kusnan",
"Mukidi",
"Sarno",
"Nurdin",
"Parmen",
"Sukinah",
"Sartini",
"Sukijan",
"Yono",
"Supoyo"
];

echo
"<pre>";
print_r(partitionFixedSubArray($employees, 5, "empty space"));
echo
"</pre>";

?>

Output:
Array
(
[0] => Array
(
[0] => Paidi
[1] => Paijo
[2] => Darno
[3] => Kusnan
[4] => Mukidi
)

[1] => Array
(
[0] => Sarno
[1] => Nurdin
[2] => Parmen
[3] => Sukinah
[4] => Sartini
)

[2] => Array
(
[0] => Sukijan
[1] => Yono
[2] => Supoyo
[3] => empty space
[4] => empty space
)

)
up
-7
ahmadz
7 years ago
function convert_to_key_case($data, $case){

$condition = ($case == 'lowercase')? 'lowercase' : 'uppercase';
$test = [];
foreach($data as $key => $value) {
if ($condition == 'lowercase') {
$test[strtolower($key)] = $value;
} else {
$test[strtoupper($key)] = $value;
}
}
return $test;
}

$input = ['test1'=>1, 'Test2' => 2, 'TeSt3' => 3];

print_r(convert_to_key_case($input, 'uppercase'));
print_r(convert_to_key_case($input, 'lowercase'));

OUTPUT

Array
(
[TEST1] => 1
[TEST2] => 2
[TEST3] => 3
)

Array (
[test1] => 1
[test2] => 2
[test3] => 3
)
up
-14
david at ramaboo dot com
15 years ago
Same as array_change_key_case only with the values. This should really be part of PHP!

<?php
/**
* @brief Returns an array with all values lowercased or uppercased.
* @return array Returns an array with all values lowercased or uppercased.
* @param object $input The array to work on
* @param int $case [optional] Either \c CASE_UPPER or \c CASE_LOWER (default).
*/
function array_change_value_case(array $input, $case = CASE_LOWER) {
switch (
$case) {
case
CASE_LOWER:
return
array_map('strtolower', $input);
break;
case
CASE_UPPER:
return
array_map('strtoupper', $input);
break;
default:
trigger_error('Case is not valid, CASE_LOWER or CASE_UPPER only', E_USER_ERROR);
return
false;
}
}
?>
up
-12
info at microweb dot lt
14 years ago
Simple function to change multidimensional array's all values to uppercase. If you would like to change to lowercase then change "mb_strtoupper" to "mb_strtolower". It works perfect for me ;)

<?php
function change_case_recursive($arr){
foreach (
$arr as $key=>$val){
if (!
is_array($arr[$key])){
$arr[$key]=mb_strtoupper($arr[$key]);
}else{
$arr[$key]=change_case_recursive($arr[$key]);
}
}
return
$arr;
}
?>
up
-22
charles
15 years ago
<?php
$input_array
= array("FirSt" => 1, "SecOnd" => 4);
print_r(array_change_key_case($input_array, CASE_UPPER));
?>
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