regexunicode - Accented characters are removed when using preg_match_all - php

I have the the problem described in title.
If I use
preg_match_all('/\pL+/u', $_POST['word'], $new_word);
and I type hello à and ì the new_word returned is *hello and *
Why?
Someone advised me to specify all characters I want to convert in this way
preg_match_all('/\pL+/u', $_POST['word'], 'aäeëioöuáéíóú');
, but I want my application works with all existing accents (for a multilanguage website).
Can you help me?
Thanks.
EDIT: I specify that I utilise this regex to purify punctuation. It well purify all punctuation but unicode characters are wrong returned, in fact are not even returned.
EDIT 2: I am sorry, but I very badly explained.
The problem is not in preg_match_all but in
str_word_count($my_key, 2, 'aäáàeëéèiíìoöóòuúù');
I had to manually specify accented characters but I think there are many others. Right?

\pL should match all utf8 characters and spaces. Be sure, that $_POST['word'] is a string encoded with utf8. If not, try utf8_encode() before matching or check the encoding of your HTML form. In my tests, your example works like a charm.
You may use this together with count() to get the number of words. Then you need not care about the possible characters. \pL will do this for you. This should do the trick:
$string = "áll thât words wíth ìntérnâtiønal çhårs";
preg_match_all('/\pL+/u', $string, $words);
echo count($words[0]); // returns: 6

Try using mb_ereg_match() (instead of preg_match()) from Multibyte String PHP library. It is specially made for working with multibyte strings.

Related

PHP strpos says different croatian chars are the same: š č

I have the following code:
$text = 'Tomáš'
echo strpos($text, "č");
# result if 4
I believe they are different chars so why is PHP telling me they are the same?
What is going on and how can I correct this?
The encoding you chose to save your source code file in cannot encode the characters you're trying to save. Whatever characters PHP is seeing, it's not comparing the strings you think it is. Save your source code in an encoding that can encode all characters, preferably UTF-8.
You should try with mb_strpos function.
Performs a multi-byte safe strpos() operation based on number of characters. The first character's position is 0, the second character position is 1, and so on.
With a regular setup, it returns false to me.
However if you've troubles with such special characters, using mb_strpos instead of strpos should help.
http://php.net/manual/en/function.mb-strpos.php

substr doesn't work fine with utf8

I am using a substr method to access the first 20 characters of a string. It works fine in normal situation, but while working on rtl languages (utf8) it gives me wrong results (about 10 characters are shown). I have searched the web but found nth useful to solve this issue. This is my line of code:
substr($article['CBody'],0,20);
Thanks in advance.
If you’re working with strings encoded as UTF-8 you may lose
characters when you try to get a part of them using the PHP substr
function. This happens because in UTF-8 characters are not restricted
to one byte, they have variable length to match Unicode characters,
between 1 and 4 bytes.
You can use mb_substr(), It works almost the same way as substr but the difference is that you can add a new parameter to specify the encoding type, whether is UTF-8 or a different encoding.
Try this:
$str = mb_substr($article['CBody'], 0, 20, 'UTF-8');
echo utf8_decode($str);
Hope this helps.
Use this instead, here is extra text to make the body long enough. This will handle multi-byte characters.
http://php.net/manual/en/function.mb-substr.php

Converting Unicode characters into the equivalent ASCII ones

I need to "flatten out" a number of Unicode strings for the purposes of indexing and searching. For example, I need to convert GötheФ€ into ASCII. The last two characters have no close representations in ASCII so it's Ok to discard them completely. So what I expect from
echo iconv("UTF-8", "ASCII//TRANSLIT//IGNORE", "GötheФ€");
is Gothe but instead it outputs Gothe?EUR.
In addition to letters, I'd also like all the variety of Unicode numerals and punctuation marks, such as periods, commas, dashes, slashes etc. to be replaced by their closest ASCII counterparts, which is something ASCII//TRANSLIT//IGNORE in iconv function does already but not without producing some garbage output for the Unicode characters for which it's not able to find any ASCII replacements. I'd like such characters to be totally ignored.
How do get the expected result? Is there a better way, perhaps using intl library?
You've picked a hard problem. It is better to tell the user entering Unicode characters to transliterate ASCII themselves. Doing it for them will only upset them when they disagree with your transliteration.
Anything you do will likely be jarring and offensive to people who place great meaning on Diacritics: http://en.wikipedia.org/wiki/Diacritic
No matter what transliteration strategy you use, you will not please everyone, since different people prescribe different meanings to different characters. A transliteration that delights one person will enrage another. You won't make everyone happy unless you let everyone use whatever character they want in Unicode.
But life is jarring and offensive, so off we go:
This PHP Code:
function toASCII( $str )
{
return strtr(utf8_decode($str),
utf8_decode(
'ŠŒŽšœžŸ¥µÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýÿ'),
'SOZsozYYuAAAAAAACEEEEIIIIDNOOOOOOUUUUYsaaaaaaaceeeeiiiionoooooouuuuyy');
}
What the above PHP function does is replace each Unicode character in the first parameter of utf8_decode and replaces it with the corresponding character in the second parameter of utf8_decode.
For example the Unicode À is transliterated to ASCII A, and the å is converted to a. You'll have to specify this for every single Unicode character that you believe transliterates to an ASCII character. For the others, remove them or run them through another transliteration algorithm.
There are 95,221 other characters that you will have to look at which might transliterate to ASCII. It becomes an existential game of "When is an A no longer an A?". What about the Klingon characters and the road-map signs that kind of look like an A? The fish character kind of looks like an a. Who is to say what is what?
This is a lot of work, but if you are cleaning database input, you have to create a white list of characters and block out the other barbarians, keeping them out at the moat, it's the only reliable way.

Is it safe to use preg_ functions with ascii-character pattern and utf-8 multibyte subject?

I know that if I use multibyte(UTF-8) characters for the pattern, I have to use mb_ functions or have to use u option for pattern of preg_ functions.
But when I use multibyte(UTF-8) characters only for the subject of preg_ functions and use only ascii characters for the pattern, do preg_ functions (without u option) work correctly?
I know that in this case I have to use mb_ function or add u option to the pattern:
$str = preg_replace("/$utf8_multibyte_pattern/", '', $str);
I want to know if this code(u option is not used) is safe or not:
$ascii_pattern = "[a-zA-Z0-9'$#\\\"%&()\-~|~=!#`{}[]:;+*/.,_<>?_\n\t\r]";
$multibyte_str = preg_replace("/$ascii_pattern/", '', $utf8_multibyte_str);
Maybe I found the answer by myself.
But someone who knows about character code well, please comment to this answer or post another answer.
According to wikipedia, UTF-8 character codes don't contain ascii code.
http://en.wikipedia.org/wiki/UTF-8#Advantages
The ASCII characters are represented by themselves as single bytes that do not appear anywhere else, which makes UTF-8 work with the majority of existing APIs that take bytes strings but only treat a small number of ASCII codes specially. This removes the need to write a new Unicode version of every API, and makes it much easier to convert existing systems to UTF-8 than any other Unicode encoding.
I think this means preg function with ascii pattern without u option is safe for multibyte(UTF8) subject.
And this code (without u option)
$multibyte_str = preg_replace("/$ascii_pattern/", '', $utf8_multibyte_str);
and this code (with u option)
$multibyte_str = preg_replace("/$ascii_pattern/u", '', $utf8_multibyte_str);
are the same.
Both correctly works.
Am I correct?
It is safe as far as I know as long as you use the unicode property (/u) like so:
$ascii_pattern = "[a-zA-Z0-9'$#\\\"%&()\-~|~=!#`{}[]:;+*/.,_<>?_\n\t\r]";
$multibyte_str = preg_replace("/$ascii_pattern/u", '', $utf8_multibyte_str);
To see more information on unicode characters, see here

Cakephp sanitizing and special characters

i'm using sanitize::paranoid on a string but i need to exclude a few special characters but it doesn't seem to work.
$content=sanitize::paranoid($content,array('à',' '));
I've changed the encoding of my file from ansi to utf8 but cakephp doesn't really like it so i need to find another way.
That array should contain the list of characters to exclude from sanitization, but it keep removing the "à" and i want those character in the final string.
Sanitize:paranoid is a simple preg_replace ($allow is just additional characters, escaped):
preg_replace("/[^{$allow}a-zA-Z0-9]/", '', $string);
As you can see, paranoid is quite paranoid... doesn't accept non-ascii letters by default.
The file where you had the à was probably saved in another encoding (working on windows?)
Anyway, if you want you can write a better filter by using /[^\p{L}]/u, which excludes letters in any lanaguage.
Taken from the Sanitize::paranoid function:
cleaned = preg_replace("/[^{$allow}a-zA-Z0-9]/", '', $string);
Because your character (à) is not in this range it will not be returned.
If you're using Cake 2.x you can override the Sanitize class in your app folder
and replace all occurrences of:
a-zA-Z0-9
with:
\w
This should return the accented character (it does for me). You can also look at the
multibyte functions if you like but that might be a problem if you're building a CMS.
it must be some special encoding problems that cakephp paranoid doesnt know
Sanitize::paranoid($badString, array(' ', '#')); # is the allowed char
it should be working. i tried this example myself

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