Question

How to convert a string lowercase characters to uppercase and uppercase to lowercase with PHP

Answer 1

$s = "Php ProGRamMinG";

$s = strtolower($s) ^ strtoupper($s) ^ $s;

echo $s; 
  
 
         
  
/*
run:
              
pHP pROgrAMmINg
       
*/

 

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Answer 2

$s = "Php ProGRamMinG";

$s = preg_replace_callback(
    '/[a-z]/i',
    function($same_chars) {
        return $same_chars[0] ^ ' ';
    },
    $s
);

echo $s; 
  
 
         
  
/*
run:
              
pHP pROgrAMmINg
       
*/

 

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Answer 3

function flip_characters($s) {
    for ($i = 0; $i < strlen($s); $i++) {
         $ch = ord($s[$i]);
         if (($ch >= 65 && $ch <= 90) || ($ch >= 97 && $ch <= 122)) {
              $s[$i] = chr($ch ^ 32);
         }
    }
    return $s;
}

$s = "Php ProGRamMinG";

$s = flip_characters($s);

echo $s; 
  
 
         
  
/*
run:
              
pHP pROgrAMmINg
       
*/

 

70+ SQL courses for beginners and professionals