PHP: Replace umlauts with closest 7-bit ASCII equivalent in an UTF-8 string

Question

What I want to do is to remove all accents and umlauts from a string, turning "lärm" into "larm" or "andré" into "andre". What I tried to do was to utf8_decode the string and then use strtr on it, but since my source file is saved as UTF-8 file, I can't enter the ISO-8859-15 characters for all umlauts - the editor inserts the UTF-8 characters.

Obviously a solution for this would be to have an include that's an ISO-8859-15 file, but there must be a better way than to have another required include?

echo strtr(utf8_decode($input), 
           'ŠŒŽšœžŸ¥µÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýÿ',
           'SOZsozYYuAAAAAAACEEEEIIIIDNOOOOOOUUUUYsaaaaaaaceeeeiiiionoooooouuuuyy');

UPDATE: Maybe I was a bit inaccurate with what I try to do: I do not actually want to remove the umlauts, but to replace them with their closest "one character ASCII" equivalent.

Solution 1

iconv("utf-8","ascii//TRANSLIT",$input);

Extended example

Solution 2

A little trick that doesn't require setting locales or having huge translation tables:

function Unaccent($string)
{
    if (strpos($string = htmlentities($string, ENT_QUOTES, 'UTF-8'), '&') !== false)
    {
        $string = html_entity_decode(preg_replace('~&([a-z]{1,2})(?:acute|cedil|circ|grave|lig|orn|ring|slash|tilde|uml);~i', '$1', $string), ENT_QUOTES, 'UTF-8');
    }

    return $string;
}

The only requirement for it to work properly is to save your files in UTF-8 (as you should already).

Solution 3

you can also try this

$string = "Fóø Bår";
$transliterator = Transliterator::createFromRules(':: Any-Latin; :: Latin-ASCII; :: NFD; :: [:Nonspacing Mark:] Remove; :: Lower(); :: NFC;', Transliterator::FORWARD);
echo $normalized = $transliterator->transliterate($string);

but you need to have http://php.net/manual/en/book.intl.php available

Solution 4

If you are using WordPress, you can use the built-in function remove_accents( $string )

https://codex.wordpress.org/Function_Reference/remove_accents

However I noticed a bug : it doesn’t work on a string with a single character.

Solution 5

Okay, found an obvious solution myself, but it's not the best concerning performance...

echo strtr(utf8_decode($input), 
           utf8_decode('ŠŒŽšœžŸ¥µÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýÿ'),
           'SOZsozYYuAAAAAAACEEEEIIIIDNOOOOOOUUUUYsaaaaaaaceeeeiiiionoooooouuuuyy');

View more solutions

Comments

[Nishan]

I had to add "setlocale(LC_ALL, 'en_US');" (sadly no locals for Germany seem to be available on my machine :( ), but then it works. Great! :)

[spikey]

Why does this solution return "o for ö on my machine and on the examples in the php reference it returns oe?

[Zebooka]

This does not work for Cyrillic characters. They are converted to ? question marks instead.

[laurent]

It's not the best in terms of performance and it also produces incorrect result. Letters like Œ, Æ, etc. should decompose to two letters, not to one.

[Matt]

This bombs with a value of false and gives me a notice that illegal characters were encountered...

[Michał Leon]

To spikey's comment: if you set your locale to de_*.UTF8 (de_DE.UTF8, de_CH.UTF8, etc.), then umlauts will be converted to *e (ü->ue). Set it to en_US..UTF8 to get the desired effect.

[edditor]

I have the same problem as spikey, setlocale stuff doesn't help also.

[Piskvor left the building]

You have missed žščřďťňů, and that's just the ones I see on my keyboard. Whitelisting known characters is not the best solution.

[PeerBr]

setlocale() depends on your operating system, is not thread-safe and wreaks havoc if you do it wrong (such as treating commas as periods in conversions). Either be careful (using LC_CTYPE instead of LC_ALL in this case) or stay away from it unless you know exactly what you're doing.

[Nishan]

@this.lau_ As mentioned in the question: I'm looking for the closest "one character ASCII", so no - two letter decomposition would not be correct for my use case. One letter is correct for what I'm looking to do.

[vinczemarton]

Works great for hungarian

[Jose Manuel Abarca Rodríguez]

Use "ascii//translit//ignore" to prevent "illegal characters encountered" error.

[Constantin Groß]

If iconv() with ASCII//TRANSLIT doesn't work for you with German umlauts (ä/ö/ü => ae/oe/ue, despite setting setlocale() to a German utf8 locale, this answer to another question was the solution for me, using transliterator_transliterate() with de-ASCII supplied via the transliterator build string.

[Vladan]

Despite not actually being an exact answer, I appreciate this answer as I'm using WordPress. So thanks! ;)