How do I detect non-ASCII characters in a string?

Question

If I have a PHP string, how can I determine if it contains at least one non-ASCII character or not, in an efficient way? And by non-ASCII character, I mean any character tha

Answer 1

I benchmarked the suggested functions as I need this check for batch processing of shorter (1000 characters max) strings. I tested 10k iterations of 30 different strings (empty, short, longer, ascii, accents, japanese, emoji, non-ascii start, non-ascii end etc). Here are the rough results:

mb_check_encoding: 95ms average. Performance degrades way faster than preg_match and ctype as the strings get longer (1MB+).

mb_check_encoding($input, 'ASCII');

preg_match: 85ms average. Decently fast for 1MB+ strings (walks the string, so faster if there are non-ascii characters early in the string).

!preg_match('/[\\x80-\\xff]/', $input);

ctype_print: 83ms average. Decently fast for 1MB+ strings (walks the string, so faster if there are non-ascii characters early in the string). DO NOTE that this is not really an ascii check.

ctype_print($input);

while/ord: 500ms average. I'm still waiting for the 1MB+ strings test to finish.

function is_ascii($input) {
    $num = 0;
    while( isset( $string[$num] ) ) {
        if( ord( $string[$num] ) & 0x80 ) {
            return false;
        }
        $num++;
    }
    return true;
}

Answer 2

You can use mb_detect_encoding and check for ASCII:

mb_detect_encoding($str, 'ASCII', true)

This will return false if $str contains at least one non-ASCI character (byte value > 0x7F).

Answer 3

Try (mb_detect_encoding)

Answer 4

The function ctype_print returns true iff all characters fall into the ASCII range 32-126 (PHP unit test).

Answer 5

I suggest you look into utf8_encode or utf8_decode under PHP's manual:

http://www.php.net/manual/en/function.utf8-encode.php

Look into the examples down below as it may have something there that leads you to the right direction if not finding what you are looking for.

Answer 6

If you do not want to deal with Regex in javascript you can do

detectUf8 : function(s) {
  var utf8=s.split('').filter(function(C) {
    return C.charCodeAt(0)>127;
  })
  return (utf8.join('').length>0);
},