How can I remove the NULL character from string

Question

I have a PHP variable that contains a string which represents an XML structure. This string contains ilegal characters that dont let me build a new SimpleXMLElement object f

Answer 1

While it's probably not the primary target of your question, please have a look at PHP's filter functions: http://www.php.net/manual/en/intro.filter.php

Filter functions validate and sanitize values. Form the PHP site:

$a = 'joe@example.org';
$b = 'bogus - at - example dot org';
$c = '(bogus@example.org)';

$sanitized_a = filter_var($a, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_a, FILTER_VALIDATE_EMAIL)) {
    echo "This (a) sanitized email address is considered valid.\n";
}

$sanitized_b = filter_var($b, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_b, FILTER_VALIDATE_EMAIL)) {
    echo "This sanitized email address is considered valid.";
} else {
    echo "This (b) sanitized email address is considered invalid.\n";
}

$sanitized_c = filter_var($c, FILTER_SANITIZE_EMAIL);
if (filter_var($sanitized_c, FILTER_VALIDATE_EMAIL)) {
    echo "This (c) sanitized email address is considered valid.\n";
    echo "Before: $c\n";
    echo "After:  $sanitized_c\n";    
}

Result:

This (a) sanitized email address is considered valid.

This (b) sanitized email address is considered invalid.

This (C) sanitized email address is considered valid.

Before: (bogus@example.org)

After: bogus@example.org

Answer 2

trim() will also remove null characters, from either end of the source string (but not within).

$text = trim($text);

I've found this useful for socket server communication, especially when passing JSON around, as a null character causes json_decode() to return null.

Answer 3

$text = str_replace("\0", "", $text);

will replace all null characters in the $text string. You can also supply arrays for the first two arguments, if you want to do multiple replacements.