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', $login)
To find more possibilities you can check the pcre documentation at: http://www.pcre.org/pcre.txt
If you need to be more precise, the best way is to use character ranges in the character class. You can find code of characters here.
Related
I was using the following regex with preg_replace to filter inputs:
/[^A-Za-z0-9[:space:][:blank:]_<>=##£€$!?:;%,.\\'\\\"()&+\\/-]/
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.
I tried to create regular expression with specification below
any alphabetic character (at least one)
any numeric character (at least one)
no spaces
accept all special characters (except ",;&|')
^(?=.*[0-9])(?=.*[a-z])(?!.*\s)((?!.*[",;&|'])|(?=(.*\W){1,}))(?!.*[",;&|'])$
This is the one I tried.
What I can do with this?
Question is still vague in nature, please provide some examples of accepted strings.
Just to get you started you can use:
character class in a negative lookahead
Don't forget start & end anchors:
Regex:
/^(?=.*?\d)(?=.*?[a-z])(?!.*?[ ",;&|']).+$/i
This regex will match 1 or more characters that are not one of ",;&|' and atleast one digit and a-z alpgabet is required.
Live Demo: http://www.rubular.com/r/nxdi79ZcRx
In PHP use it like this:
'/^(?=.*?\d)(?=.*?[a-z])(?!.*?[ ",;&|\']).+$/i'
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
Testing the PHP regex engine, I see that it considers only [0-9A-Za-z_] to be word characters. Letters of non-ASCII languages, such as Hebrew, are not matched as word characters with [\w]. Are there any PHP or Perl regex escape sequences which will match a letter in any language? I could add ranges for each alphabet that I expect to be used, but users will always surprise us with unexpected languages!
Note that this is not for security filtering but rather for tokenizing a text.
Try [\pL_] - see the reference at
http://php.net/manual/en/regexp.reference.unicode.php
Try \p{L}. It matches any kind of letter from any language. If you don't want to use char set [].
I am using utf8 format to store all my data into mysql. Before data is inserted into the database I need to clean the strings with unwanted characters. The strings are in utf8 format. I know how to use regex and string replace but do not know how to work with arabic characters.
Sample string that needs to be cleaned : "████ .. الــقــوانين الجديـــدة في قســـم الـعنايـ";
Thanking you
Ok. As #Jonathan Leffler already said, if you can specify the unicode character ranges for the characters that need to be replaced, you can use a regular expression to replace the characters with an empty string.
A unicode character is specified as \x{FFFF} in an expression (in PHP). In addition, you have to set the u modifier to make PHP treat the pattern as UTF8.
So in the end, you have something like this:
preg_replace('/[\x{FFFF}-\x{FFFF}]+/u','',$string);
where
/.../u are the delimiters plus the modifier
[...]+ is a character class plus quantifier, which means match any of these characters inside one or mor times
\x{FFFF}-\x{FFFF} is a unicode character range (obviously you have to provide the right codepoints/numbers of the characters).
You can also negate the group with a ^ you can specify the range which you want to keep:
preg_replace('/[^\x{FFFF}-\x{FFFF}]+/u','',$string);
More information:
Regular expressions
Regular expressions in PHP
Unicode Charts