php - Remove non-ascii characters from string

Question

I'm getting strange characters when pulling data from a website:

?

How can I remove anything that isn't a non-extended ASCII character?

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A more appropriate question can be found here: PHP - replace all non-alphanumeric chars for all languages supported

Answer 1

A regex replace would be the best option. Using $str as an example string and matching it using :print:, which is a POSIX Character Class:

$str = 'aA?';
$str = preg_replace('/[[:^print:]]/', '', $str); // should be aA

What :print: does is look for all printable characters. The reverse, :^print:, looks for all non-printable characters. Any characters that are not part of the current character set will be removed.

Note: Before using this method, you must ensure that your current character set is ASCII. POSIX Character Classes support both ASCII and Unicode and will match only according to the current character set. As of PHP 5.6, the default charset is UTF-8.