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    array_change_key_case

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

    array_change_key_case — Changes 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 add a note

    User Contributed Notes 20 notes

    up
    25
    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
    5 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
    1
    wendri dot net at gmail dot com
    2 years 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
    10
    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
    1
    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
    2
    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
    0
    shaman_master at list dot ru
    5 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
    -1
    gsoft
    1 year 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
    -3
    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
    -3
    NetPanther
    12 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
    14 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
    -5
    Luis Henrique Pessoa
    14 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
    17 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
    -6
    JOE
    13 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
    -4
    cm at gameswelt dot de
    17 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
    -5
    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 $res;
        }
    }
    up
    -7
    ahmadz
    8 years ago
    function convert_to_key_case($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
    -10
    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
    -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
    -21
    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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