I was using the following regex with preg_replace to filter inputs:
/[^A-Za-z0-9[:space:][:blank:]_<>=##£€$!?:;%,.\\'\\\"()&+\\/-]/
However this does not allow accented characters like umlauts so I changed it to:
/[^\w[:space:][:blank:]_<>=##$£€!?:;%,.\\'\\\"()&+\\/-]/u
This however does work with the £ or € characters, nothing is returned, but I need to accept these characters, I have tried escaping them but that doesn't work.
Also I want to create an regex that is similar to just A-Za-z but will allow accented characters, how can I do that?
From http://php.net/manual/en/reference.pcre.pattern.modifiers.php
u (PCRE_UTF8) This modifier turns on additional functionality of PCRE
that is incompatible with Perl. Pattern and subject strings are
treated as UTF-8. An invalid subject will cause the preg_* function to
match nothing; an invalid pattern will trigger an error of level
E_WARNING. Five and six octet UTF-8 sequences are regarded as invalid
since PHP 5.3.4 (resp. PCRE 7.3 2007-08-28); formerly those have been
regarded as valid UTF-8.
That means that first you have to make sure the input string is proper UTF-8 text.
Secondly, have you heard of unicode categories? If not, head to http://www.regular-expressions.info/unicode.html and search for Unicode categories. For example you could use \p{S} to match all currency symbols, or \p{L} for all letters. Your regex could (probably) be written as follows: /[^\p{L}\p{P}\p{N}\p{S}\p{M}]/.
This will though match pretty much nothing, as it allows pretty much all characters to be used - ^ at the start of a regex character class (something between [ and ]) means "everything that is not what is in this class will be matched".
On top of that, your regex will only match input that has a length of exactly one - if you want to match everything, you should begin adding a + after your closing ] to keep matching characters until the pattern fails.
So, for that sake, what exactly are you trying to achieve? Maybe we can suggest you some more regex improvements if we know what you're trying to do.
Related
I'm trying to write a reasonably permissive validator for names in PHP, and my first attempt consists of the following pattern:
// unicode letters, apostrophe, hyphen, space
$namePattern = "/^([\\p{L}'\\- ])+$/";
This is eventually passed to a call to preg_match(). As far as I can tell, this works with your vanilla ASCII alphabet, but seems to trip up on spicier characters like Ă or 张.
Is there something wrong with the pattern itself? Perhaps I'm expecting \p{L} to do more work than I think it does?
Or does it have something to do with the way input is being passed in? I'm not sure if it's relevant, but I did make sure to specify a UTF8 encoding on the form page.
I think the problem is much simpler than that: You forgot to specify the u modifier. The Unicode character properties are only available in UTF-8 mode.
Your regex should be:
// unicode letters, apostrophe, hyphen, space
$namePattern = '/^[-\' \p{L}]+$/u';
If you want to replace Unicode old pattern with new pattern you should write:
$text = preg_replace('/\bold pattern\b/u', 'new pattern', $text);
So the key here is u modifier
Note : Your server php version shoud be at least PHP 4.3.5
as mentioned here php.net | Pattern Modifiers
u (PCRE_UTF8)
This modifier turns on additional functionality of PCRE that is incompatible with Perl. Pattern strings are treated as UTF-8. This
modifier is available from PHP 4.1.0 or greater on Unix and from PHP
4.2.3 on win32. UTF-8 validity of the pattern is checked since PHP 4.3.5.
Thanks AgreeOrNot who give me that key here preg_replace match whole word in arabic
I tried it and it worked in localhost but when I try it in remote server it didn't work, then I found that php.net start use u modifier in PHP 4.3.5. , I upgrade php version and it works
Its important to know that this method is very helpful for Arabic users (عربي) because - as I believe - unicode is the best encode for arabic language, and replacement will not work if you don't use the u modifier, see next example it should work with you
$text = preg_replace('/\bمرحبا بك\b/u', 'NEW', $text);
First of all, your life would be a lot easier if you'd use single apostrophes instead of double quotes when writing these -- you need only one backslash. Second, combining marks \pM should also be included. If you find a character not matched please find out its Unicode code point and then you can use http://www.fileformat.info/info/unicode/ to figure out where it is. I found http://hsivonen.iki.fi/php-utf8/ an invaluable tool when doing debugging with UTF-8 properties (don't forget to convert to hex before trying to look up: array_map('dechex', utf8ToUnicode($text))).
For example, Ă turns out to be http://www.fileformat.info/info/unicode/char/0102/index.htm and to be in Lu and so L should match it and it does match for me. The other character is http://www.fileformat.info/info/unicode/char/5f20/index.htm and is also isLetter and indeed matches for me. Do you have the Unicode character tables compiled in?
Anyone else looking here and not getting this to work, please note that /u will not produce consistent result with Unicode scripts across different PHP versions.
See example: https://3v4l.org/4hB9e
Related: Incosistent regex result for Thai characters across different PHP version
<?php preg_match('/[a-zığüşöç]/u',$title) ?>
I'm trying to write a reasonably permissive validator for names in PHP, and my first attempt consists of the following pattern:
// unicode letters, apostrophe, hyphen, space
$namePattern = "/^([\\p{L}'\\- ])+$/";
This is eventually passed to a call to preg_match(). As far as I can tell, this works with your vanilla ASCII alphabet, but seems to trip up on spicier characters like Ă or 张.
Is there something wrong with the pattern itself? Perhaps I'm expecting \p{L} to do more work than I think it does?
Or does it have something to do with the way input is being passed in? I'm not sure if it's relevant, but I did make sure to specify a UTF8 encoding on the form page.
I think the problem is much simpler than that: You forgot to specify the u modifier. The Unicode character properties are only available in UTF-8 mode.
Your regex should be:
// unicode letters, apostrophe, hyphen, space
$namePattern = '/^[-\' \p{L}]+$/u';
If you want to replace Unicode old pattern with new pattern you should write:
$text = preg_replace('/\bold pattern\b/u', 'new pattern', $text);
So the key here is u modifier
Note : Your server php version shoud be at least PHP 4.3.5
as mentioned here php.net | Pattern Modifiers
u (PCRE_UTF8)
This modifier turns on additional functionality of PCRE that is incompatible with Perl. Pattern strings are treated as UTF-8. This
modifier is available from PHP 4.1.0 or greater on Unix and from PHP
4.2.3 on win32. UTF-8 validity of the pattern is checked since PHP 4.3.5.
Thanks AgreeOrNot who give me that key here preg_replace match whole word in arabic
I tried it and it worked in localhost but when I try it in remote server it didn't work, then I found that php.net start use u modifier in PHP 4.3.5. , I upgrade php version and it works
Its important to know that this method is very helpful for Arabic users (عربي) because - as I believe - unicode is the best encode for arabic language, and replacement will not work if you don't use the u modifier, see next example it should work with you
$text = preg_replace('/\bمرحبا بك\b/u', 'NEW', $text);
First of all, your life would be a lot easier if you'd use single apostrophes instead of double quotes when writing these -- you need only one backslash. Second, combining marks \pM should also be included. If you find a character not matched please find out its Unicode code point and then you can use http://www.fileformat.info/info/unicode/ to figure out where it is. I found http://hsivonen.iki.fi/php-utf8/ an invaluable tool when doing debugging with UTF-8 properties (don't forget to convert to hex before trying to look up: array_map('dechex', utf8ToUnicode($text))).
For example, Ă turns out to be http://www.fileformat.info/info/unicode/char/0102/index.htm and to be in Lu and so L should match it and it does match for me. The other character is http://www.fileformat.info/info/unicode/char/5f20/index.htm and is also isLetter and indeed matches for me. Do you have the Unicode character tables compiled in?
Anyone else looking here and not getting this to work, please note that /u will not produce consistent result with Unicode scripts across different PHP versions.
See example: https://3v4l.org/4hB9e
Related: Incosistent regex result for Thai characters across different PHP version
<?php preg_match('/[a-zığüşöç]/u',$title) ?>
I'm trying to write a reasonably permissive validator for names in PHP, and my first attempt consists of the following pattern:
// unicode letters, apostrophe, hyphen, space
$namePattern = "/^([\\p{L}'\\- ])+$/";
This is eventually passed to a call to preg_match(). As far as I can tell, this works with your vanilla ASCII alphabet, but seems to trip up on spicier characters like Ă or 张.
Is there something wrong with the pattern itself? Perhaps I'm expecting \p{L} to do more work than I think it does?
Or does it have something to do with the way input is being passed in? I'm not sure if it's relevant, but I did make sure to specify a UTF8 encoding on the form page.
I think the problem is much simpler than that: You forgot to specify the u modifier. The Unicode character properties are only available in UTF-8 mode.
Your regex should be:
// unicode letters, apostrophe, hyphen, space
$namePattern = '/^[-\' \p{L}]+$/u';
If you want to replace Unicode old pattern with new pattern you should write:
$text = preg_replace('/\bold pattern\b/u', 'new pattern', $text);
So the key here is u modifier
Note : Your server php version shoud be at least PHP 4.3.5
as mentioned here php.net | Pattern Modifiers
u (PCRE_UTF8)
This modifier turns on additional functionality of PCRE that is incompatible with Perl. Pattern strings are treated as UTF-8. This
modifier is available from PHP 4.1.0 or greater on Unix and from PHP
4.2.3 on win32. UTF-8 validity of the pattern is checked since PHP 4.3.5.
Thanks AgreeOrNot who give me that key here preg_replace match whole word in arabic
I tried it and it worked in localhost but when I try it in remote server it didn't work, then I found that php.net start use u modifier in PHP 4.3.5. , I upgrade php version and it works
Its important to know that this method is very helpful for Arabic users (عربي) because - as I believe - unicode is the best encode for arabic language, and replacement will not work if you don't use the u modifier, see next example it should work with you
$text = preg_replace('/\bمرحبا بك\b/u', 'NEW', $text);
First of all, your life would be a lot easier if you'd use single apostrophes instead of double quotes when writing these -- you need only one backslash. Second, combining marks \pM should also be included. If you find a character not matched please find out its Unicode code point and then you can use http://www.fileformat.info/info/unicode/ to figure out where it is. I found http://hsivonen.iki.fi/php-utf8/ an invaluable tool when doing debugging with UTF-8 properties (don't forget to convert to hex before trying to look up: array_map('dechex', utf8ToUnicode($text))).
For example, Ă turns out to be http://www.fileformat.info/info/unicode/char/0102/index.htm and to be in Lu and so L should match it and it does match for me. The other character is http://www.fileformat.info/info/unicode/char/5f20/index.htm and is also isLetter and indeed matches for me. Do you have the Unicode character tables compiled in?
Anyone else looking here and not getting this to work, please note that /u will not produce consistent result with Unicode scripts across different PHP versions.
See example: https://3v4l.org/4hB9e
Related: Incosistent regex result for Thai characters across different PHP version
<?php preg_match('/[a-zığüşöç]/u',$title) ?>
I'm using PHP Version 5.3.27
I'm trying to get my regex to match whitespace, and special characters such as ♦◘•♠♥☻, the other known special characters which are %$#&*# are already matched, but somehow the ones I mentioned before are not matched..
Current regex
preg_match('/^[a-zA-Z0-9[:space:]]+$/', $login)
My apology for asking two questions on the same subject. I hope this one is clear enough for you.
use this
[\W]+
will match any non-word character.
Your regex doesn't contain any reference to the special characters mentioned. You would need to include them in the character class for them to be matched.
To match those kinds of special characters you can use the unicode values.
Example:
\u0000-\uFFFF
\x00-\xFF
The top is UTF-16, the bottom is UTF-8.
Refer to a UTF-8/16 character table online to match up your symbols with their unicode values, then create a range to keep your expression short.
You can use the \p{S} character class (or \p{So}) that matches symbol characters (that includes this kind of characters: ╭₠☪♛♣♞♉♆☯♫):
preg_match('/^[a-zA-Z0-9\h\p{S}]+$/u', $login)
To find more possibilities you can check the pcre documentation at: http://www.pcre.org/pcre.txt
If you need to be more precise, the best way is to use character ranges in the character class. You can find code of characters here.
I write a regex that should extracts following patterns;
"çççoookkk gggüüüzzzeeelll" (it means vvveeerrryyy gggoooddd with turkish characters "ç" and "ü")
"ccccoookkk ggguuuzzzeeelll" (it means the same but with english characters "c" and "u")
here is the regular expressions i'm trying;
"\b[çc]+o+k+\sg+[üu]+z+e+l+\b" : this works in english but not in turkish characters
"çok": finds "çok" but when i try "ç+o+k+" doesn't work for "çççoookkk", it finds "çoookkk"
"güzel": finds "güzel" but when i try "g+ü+z+e+l+" doesn't work for "gggüüüzzzeeelll"
"\b(c+o+k+)|(ç+o+k+)\s(g+u+z+e+l)|(g+ü+z+e+l+)\b": doesn't work properly
"[çc]ok\sg[uü]zel": I also tried this to get "çok güzel" pattern but doesn't work neither.
I thing the problem might be using regex operators with turkish characters. I don't know how can i solve this.
I am using http://www.myregextester.com to check if my regular expressions are correct.
I am using Php programming language to get a specific pattern from searched tweets via Twitter Rest Api.
Thanks,
You have not specified what programming language you are using, but in many of them, the \b character class can only be used with plain ASCII encoding.
Internally, \b is processed as a boundary between \w and \W sets.
In turn, \w is equal to [a-zA-Z0-9_].
If you are not using any fancy space marks (you shouldn't), then consider using regular whitespace char classes (\s).
See this table (scroll down to Word Boundaries section) to check if your language supports Unicode for \b. If it says, "ascii", then it does not.
As a side note, depending on your programming language, you may consider using direct Unicode code points instead of national characters.
Se also: utf-8 word boundary regex in javascript
Further reading:
An excellent article about using Unicode characters in regular expressions
An article for word boundaries
List of Turkish Unicode code points