Comparing Unicode Characters in PHP

Question

I am unable to compare two unicode characters that to my mind should be exactly the same. I suspect that somehow they are encoded differently, but don't know how to change them to the same encoding.

The characters I want to compare are from the Myanmar Unicode block. I'm running wordpress on php 5 and am trying to make a custom plugin to handle Myanmar Unicode. All my files are encoded in UTF-8, but I don't know what wordpress does.

Here is what I'm doing:

function myFunction( $inputText ) {
    $outputText = '';
    $inputTextArray = str_split($inputText);
    foreach($inputTextArray as $char) {
        if ($char == "က") // U+1000, a character from the Myanmar Unicode block 
            $outputText .= $char;
    }
    return $outputText;
}
add_filter( 'the_content', 'myFunction');

At this stage in working things out, the function is supposed to only return က where it appears in the content. However, it never returns anything but empty strings, even when က is clearly present in the post content. If I change the character to any latin characters, the function works as expected.

So, my question is, how do I encode these characters (either $char or "က") so that when $char contains this character, they compare equal.

Please can you add $value = unpack('H*', $inputText); echo base_convert($value[1], 16, 2); echo $value; And give use the output? That function converts strings to binary btw. — Danack, Jan 18 '13 at 05:39
oops - fixed conversion to binary. It's from here http://stackoverflow.com/questions/6382738/convert-string-to-binary-then-back-again-using-php — Danack, Jan 18 '13 at 05:41
Ok, in the post title, where I put only a single က, it returns `111000011000000010000000Array`. — Ben Sharon, Jan 18 '13 at 05:48

Shiplu Mokaddim · Accepted Answer · 2013-01-18T06:03:45.323

2

str_split is not unicode aware. For multibyte characters it'll split the them in single character. Try to use either multi-byte string functions or preg_split with /u switch

$inputTextArray = preg_split("//u", $inputText, -1, PREG_SPLIT_NO_EMPTY);

http://codepad.viper-7.com/ErFwcy

Using multi-byte function mb_substr_count you can reduce your code too. Like this,

function myFunction( $inputText ) {
    return str_repeat("က", mb_substr_count($inputText, "က"));
}

Or using regular expression,

preg_match_all("/က/u", $text, $match);
$output = implode("", $match[0]);

edited Jan 18 '13 at 06:03

answered Jan 18 '13 at 05:45

Shiplu Mokaddim

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Wow, that does it. Thank you so much. – Ben Sharon Jan 18 '13 at 05:53
It may be worth turing on mbstring by default: http://php.net/manual/en/mbstring.overload.php – Danack Jan 18 '13 at 05:55
@Danack no for many reasons but most importantly for the reason of losing byte level functions – Esailija Jan 18 '13 at 05:58
@BenSharon see the update, what you were requiring was much simpler. – Shiplu Mokaddim Jan 18 '13 at 06:04

Comparing Unicode Characters in PHP

1 Answers1