array_change_key_case

Unicode example;<?phpfunction 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)

Here is the most compact way to lower case keys in a multidimensional arrayfunction 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));}

I improve the array_change_key_case_recursive function ,let it can lowercase or uppercase keysfunction 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));}

Improved multidimensional unicode func (after qeremy):<?phpfunction 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        ))

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;    }?>

<?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)    );}?>

Array of partitions with always the same number of sub-array indexes.<?phpfunction 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        ))

Use this to capitalize first letter of all array keys:<?phpfunction 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 )

I just changed the code a little bit so you havent got a code that repeats itself.<?phpfunction 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)*/

<?phpfunction 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;}?>

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;
    }
?>

//Array key case change recursively (Unicode):<?phpfunction 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;}