Question

How to check if a string contains only unique characters in PHP

Answer 1

function sort_string($s) {
    $arr = str_split($s);
    sort($arr);
      
    return implode('', $arr); 
}
function contains_unique_chars($s) { 
    
    $s = sort_string($s);
    
    for ($i = 0; $i < strlen($s) - 1; $i++) { 
         if ($s[$i] == $s[$i + 1]) {
              return false; 
         } 
    }
    return true; 
} 
  


$s = "abcd"; 

if (contains_unique_chars($s)) {
    echo "yes";
}
else {
   echo "no"; 
}
   
         

    
/*
run:

yes
         
*/

 

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