只允许英文字符/字母/数字和一些特殊字符[重复]

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• PHP: Allow only certain characters in string, without using regex 1 answer

My problem is that I am making a small search engine from scratch, but it gets messed up if I search in Russian/any other language besides English. I was hoping some one could give me a code with regex that could filter out (not just detect, automaticallt filter out) Russian letters, or any other letters except the English letters, and keyboard special characters (-/:;()$&@". - etc). Later on, I will implement different language support for my engine, but for now, I want to finish the base of the engine.

Thanks in advance.

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Answer 1

You may create an array of allowed characters and then filter those that are not allowed:

$allowed = array_merge(range('a', 'z'), range('A', 'Z'), range(0, 9), array(' ', '+', '/', '-', '*', '.')); // Create an array of allowed characters

$string = 'This is allowed and this not é Ó ½ and nothing 123.'; // test string

$array = str_split($string); // split the string (character length = 1)

echo implode('', array_intersect($array, $allowed)); // Filter and implode !

Online demo.