PHP function to remove occurrences of certain characters from a string

Question

I need a PHP function that will take a string as input, and return the string minus all occurrences of these characters: ! * ' ( ) ; : @ & = + $ , / ? % # [ ]

Is there something already built for this purpose or can it be accomplished with regex? I'd rather not do 20 different str_replace function calls on this string. Thanks!

It sounds like you need whitelisting more than blacklisting. What do you want to allow? — chelmertz
– chelmertz, Commented Feb 24, 2011 at 17:56
@chelmertz, really I just need to remove those exact characters from a string. Everything else is fair game. — Casey Flynn
– Casey Flynn, Commented Feb 24, 2011 at 18:11

rojoca · Accepted Answer · 2011-02-24 18:00:18Z

1

You can use str_replace with arrays:

// $arrayOfCharsToReplace = array('!','*', ...etc

$clean = str_replace(
    $arrayOfCharsToReplace, 
    array_fill(0, count($arrayOfCharsToReplace), ''), // array of empty strings
    $unclean
);

You can also use strtr like so:

// $arrayOfReplacements = array('!' => '', '*' => '', ...etc

$clean = strtr($unclean, $arrayOfReplacements);

answered Feb 24, 2011 at 18:00

rojoca

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Linus Kleen · Accepted Answer · 2011-02-24 17:57:42Z

1

$quoted = preg_quote('!*\'();:@&=+$,/?%#[]','/');
$sanitized = preg_replace('/['.$quoted.']/', '', $string);

If in general, you'd like punctuation replaced, use a regex class instead (it's shorter and readable):

$sanitized = preg_replace('/[[:punct:]]/', '', $string);

answered Feb 24, 2011 at 17:57

Linus Kleen

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Comments

vissi · Accepted Answer · 2011-02-24 17:56:30Z

0

You can use strtr (this is preferred) or preg_replace (this is slower).

answered Feb 24, 2011 at 17:56

vissi

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