PHP, Structures and Functions of ARRAY

This function returns an array with its keys lower or uppercased, or FALSE if $array is not an ARRAY.

This function may have problems with accented characters.


<?php

arr array_change_key_case ( arr $array [, int $case = CASE_LOWER ] )


where,

$array = The working array

$case = To control whether lower or upper case

?>

$array

The working array.

$case

To control whether lower or upper case.

CASE
CONSTANT	VALUE	PURPOSE
CASE_LOWER	0	Change to lowercase
CASE_UPPER	1	Change to UPPERCASE
ed48

EXERCISE


<?php

$basearray01 = ['continents' => 
                                  ['South America', 'Europe', 'Asia'], 
                        'countries' => 
                                  ['Brasil', 'Portugal', 'Japan']];  

var_export($basearray01);

echo '<br>';

$key01 = array_keys($basearray01);

echo '<br>';

var_export($key01);

echo '<br><br><br>';

$chgcase01 = CASE_UPPER;

$basearray01a = 
          array_change_key_case($basearray01, $chgcase01);

var_export($basearray01a);

echo '<br>';

$key01a = array_keys($basearray01a);

echo '<br>';

var_export($key01a);

?>

RESULT

array ( 'continents' => array ( 0 => 'South America', 1 => 'Europe', 2 => 'Asia', ), 'countries' => array ( 0 => 'Brasil', 1 => 'Portugal', 2 => 'Japan', ), )

array ( 0 => 'continents', 1 => 'countries', )

array ( 'CONTINENTS' => array ( 0 => 'South America', 1 => 'Europe', 2 => 'Asia', ), 'COUNTRIES' => array ( 0 => 'Brasil', 1 => 'Portugal', 2 => 'Japan', ), )

array ( 0 => 'CONTINENTS', 1 => 'COUNTRIES', )

EXERCISE


<?php

$basearray02 = ["EDforty-EIGHT" => "PHP", 
                  "edFORTY-eight" => "Apache"];

print_r($basearray02);

echo '<br>';

$key02 = array_keys($basearray02);

echo '<br>';

print_r($key02);

echo '<br><br><br>';

$chgcase02 = CASE_LOWER;

$basearray02a = 
          array_change_key_case($basearray02, $chgcase02);

print_r($basearray02a);

echo '<br>';

$key02a = array_keys($basearray02a);

echo '<br>';

print_r($key02a);

?>

RESULT

Array ( [EDforty-EIGHT] => PHP [edFORTY-eight] => Apache )

Array ( [0] => EDforty-EIGHT [1] => edFORTY-eight )

Array ( [edforty-eight] => Apache )

Array ( [0] => edforty-eight )

EXERCISE


<?php

$basearray03 = array (1 => array (3, 7), 2 => array (11, 13));

var_dump($basearray03);

echo '<br>';

$key03 = array_keys($basearray03);

echo '<br>';

var_dump($key03);

echo '<br><br><br>';

$chgcase03 = CASE_LOWER;

$basearray03a = 
           array_change_key_case($basearray03, $chgcase03);

var_dump($basearray03a);

echo '<br>';

$key03a = array_keys($basearray03a);

echo '<br>';

var_dump($key03a);

?>

RESULT

array(2) { [1]=> array(2) { [0]=> int(3) [1]=> int(7) } [2]=> array(2) { [0]=> int(11) [1]=> int(13) } }

array(2) { [0]=> int(1) [1]=> int(2) }

array(2) { [1]=> array(2) { [0]=> int(3) [1]=> int(7) } [2]=> array(2) { [0]=> int(11) [1]=> int(13) } }

array(2) { [0]=> int(1) [1]=> int(2) }

EXERCISE


<?php

$basearray04 = array ("EDforty-EIGHT" => "PHP", 
                  "edFORTY-eight" => "Apache", 
                  "EDFORTY-EIGHT" => "MySQL" );

var_export($basearray04);

echo '<br>';

$key04 = array_keys($basearray04);

echo '<br>';

var_export($key04);

echo '<br><br><br>';

$chgcase04 = -10.76;

$basearray04a = 
          array_change_key_case($basearray04, $chgcase04);

var_export($basearray04a);

echo '<br>';

$key04a = array_keys($basearray04a);

echo '<br>';

var_export($key04a);

?>

EXERCISE


<?php

$var05 = "EDforty-eight";

var_export($var05);

echo '<br>';

$chgcase05 = 0;

$var05a = array_change_key_case($var05, $chgcase05);

var_export($var05a);

echo '<br>';

$key05a = array_keys($var05a);

echo '<br>';

var_export($key05a);

?>