How To Clean Special Characters From PHP String

If you are looking for the PHP special characters clean function then this post might be useful for you. This function can used to remove special character as well as able to replace specific character with other equivalent character or string.

Here is detailed explanation of function:

$specialCharacters Array: This array used to replace special character with other character or string. if you want to interchange (+) with (plus) then you need to specify in the array. You can add/remove array element according to your requirement.

strtr function: This function used to replace other language special characters to plain English character. You can remove this line safely but ensure before that these characters not in your string and you don’t need to remove them.
Last 4 line used to remove other unknown unwanted special characters.

[sourcecode language='php']
function just_clean($string)
// Replace other special chars
$specialCharacters = array(
‘#’ => ”,
‘$’ => ”,
‘%’ => ”,
‘&’ => ”,
‘@’ => ”,
‘.’ => ”,
‘€’ => ”,
‘+’ => ”,
‘=’ => ”,
‘§’ => ”,
‘\\’ => ”,
‘/’ => ”,

while (list($character, $replacement) = each($specialCharacters)) {
$string = str_replace($character, ‘-‘ . $replacement . ‘-‘, $string);

$string = strtr($string,
“ÀÁÂÃÄÅ? áâãäåÒÓÔÕÖØòóôõöøÈÉÊËèéêëÇçÌÍÎÏìíîïÙÚÛÜùúûüÿÑñ”,

// Remove all remaining other unknown characters
$string = preg_replace(‘/[^a-zA-Z0-9\-]/’, ‘ ‘, $string);
$string = preg_replace(‘/^[\-]+/’, ”, $string);
$string = preg_replace(‘/[\-]+$/’, ”, $string);
$string = preg_replace(‘/[\-]{2,}/’, ‘ ‘, $string);

return $string;

30 thoughts on “How To Clean Special Characters From PHP String”

  1. Thanks for this post.

    Can you send me the full source code in plain text document (Notepad)? The code is malformed when I copy and paste from this post.


  2. Thanks to inform me for malformed code. I have corrected formatting issue. You can now copy code to clip board easily. Let me know if you still have trouble copying code.


  3. It looks like on line 17 the website didn’t filter the post code since it has some raw HTML on it. “”
    Removing it solved the problem but now one persists.

    I entered: “Água do Lúso” and the returned string was: “n guaOdoOLn so”

  4. PS: WordPress ate what I said between the first quotes.
    There was suposed to be there:

    LowerThan /code GreaterThan

  5. Just to say that I had problems cut&pasting the code from Firefox – it messed up the special characters – but when I viewed the page in Chrome it displayed fine.

  6. here’s an array or error to correct letter i’ve started collecting.
    i messed up with my character encoding into mySql database and had to figure out the correlation.
    hope this saves someone else the time.

    $weirdArray=array(array(“ü”,”ü”), array(“ö”,”ö”), array(“ø”,”ø”), array(“é”,”é”), array(“ß”,”ss”), array(“Ã¥”, “å”) , array(“ä”, “ä”), array(“æ”, “æ”), array(“Ã…”, “Å”), array(“Ä”, “Ä”), array(“Æ”, “Æ”), array(“æ”,”æ”), array(“é”,”é”), array(“ø”,”ø”), array(“Æ”,”Æ”), array(“á”,”á”), array(“è”,”è”), array(“ı”,”?”), array(“Ö”, “Ö”), array(“Ø”,”Ø”), array(“ô”, “”), array(“”, “”), array(“ó”, “ó”), array(“ð”, “ð”), array(“º “, “”), array(“’”, “”), array(“Â’”, “”));

  7. I need to remove/replace all special language charakters, to store file safely.
    I tried this code for testing, but it doesn’t work.
    Where could be the problem?

    $name = $_FILES['file']['name'];
    $name = mb_convert_case($name, MB_CASE_LOWER, “UTF-8″);
    $name = strtr($name, “áä??é?í???óôš?ú?ýž”, “aacdeeillnoostuuyz”);

    Example of what this code does:
    from: TÉŠ?OVACÍ SÚBOR ?
    to: tsn?a??ovacst ssubor yz
    It should be:
    to: testovaci subor l

  8. @boys arab
    you can use
    preg_replace(‘/[^\x{0600}-\x{06FF}A-Za-z !@#$%^&*()]/u’,”, $text )

    to clean text with arabic chars

  9. @Awkens @Darkblack

    add below line before while:
    array_push($specialCharacters,array(‘ ‘=>’*’,));


  10. @Awkens @Darkblack

    add below line before while:
    $specialCharacters[' '] = ‘*';


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