CODEWITHSUNDEEP
phpstringpreg-replace
Nico Enking
Nico Enking

Reputation: 49

preg_replace gives back empty string

//Chars to be replaced      
$suchmuster = array();
$suchmuster[0] = 'á';
$suchmuster[1] = 'à';
$suchmuster[2] = 'â';

$suchmuster[3] = 'é';
$suchmuster[4] = 'è';
$suchmuster[5] = 'ê';

$suchmuster[6] = 'í';
$suchmuster[7] = 'ì';
$suchmuster[8] = 'î';

$suchmuster[9] = 'ó';
$suchmuster[10] = 'ò';
$suchmuster[11] = '/ô/';

$suchmuster[12] = 'ú';
$suchmuster[13] = 'ù';
$suchmuster[14] = 'û';

$suchmuster[15] = ' ';
$suchmuster[16] = '.';
$suchmuster[17] = ',';
$suchmuster[18] = '-';
$suchmuster[19] = '_';

//Replaces

$ersetzungen = array();
$ersetzungen[0] = 'a';
$ersetzungen[1] = 'a';
$ersetzungen[2] = 'a';

$ersetzungen[3] = 'e';
$ersetzungen[4] = 'e';
$ersetzungen[5] = 'e';

$ersetzungen[6] = 'i';
$ersetzungen[7] = 'i';
$ersetzungen[8] = 'i';

$ersetzungen[9] = 'o';
$ersetzungen[10] = 'o';
$ersetzungen[11] = 'o';

$ersetzungen[12] = 'u';
$ersetzungen[13] = 'u';
$ersetzungen[14] = 'u';

$ersetzungen[15] = '';
$ersetzungen[16] = '';
$ersetzungen[17] = '';
$ersetzungen[18] = '';
$ersetzungen[19] = '';

$newmessage = preg_replace($suchmuster, $ersetzungen, strtolower($message));

The above code was created to replace some special chars with normal ones but no matter which $nachricht (= $message) I put in, it always gives back an empty string!

Thanks for your help.

EDIT

I Changed it to:

//Chars to be replaced

$suchmuster[0] = '/ /';
$suchmuster[1] = '/./';
$suchmuster[2] = '/,/';
$suchmuster[3] = '/-/';
$suchmuster[4] = '/_/';

//Replaces

$ersetzungen[0] = '';
$ersetzungen[1] = '';
$ersetzungen[2] = '';
$ersetzungen[3] = '';
$ersetzungen[4] = '';

$newmessage = iconv('UTF-8', 'ISO-8859-1//TRANSLIT//IGNORE', strtolower($message));

$newmessage = preg_replace($suchmuster, $ersetzungen, $newmessage);

It still gives back an empty string.

Upvotes: 1

Views: 389

Answers (3)

Kaii
Kaii

Reputation: 20540

Regarding your updated question:

Regular expressions use special control characters. In your case it is /./ which causes your result to be empty. . means "any character" in regex, so you are replacing each and every character with nothing.

use preg_quote() to escape special characters in regular expressions. Example: $xy = '/' . preg_quote('.') . '/';

But you can do this much simpler without using regular expressions, like:

$replaces = array(
    '.' => '',
    ',' => '',
    // ...
);
$message = str_replace(array_keys($replaces), array_values($replaces), $message);

Upvotes: 1

Marcel Korpel
Marcel Korpel

Reputation: 21763

Instead of using several patterns, you can also combine the pattern to:

$nachrichtneu = preg_replace('/[,.\s_-]/', '', $nachrichtneu);

And strtolower will not convert Á and the like to á. First do the iconv conversion, then the strtolower.

Upvotes: 1

Ulrich Horus
Ulrich Horus

Reputation: 350

change your code through

$suchmuster = array();
$suchmuster[0] = "/á/";
$suchmuster[1] = "/à/";

...

Upvotes: 0

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