I am trying to select only capital letters in polytonic Greek text using regex. The specific application is PHP, but I had trouble with it so I started playing around with it in RegExr:
https://regexr.com/6ellt
([Α-ΩΗΙΟΥΩᾼῌῼΡΆΈΉΊΌΎΏᾺῈῊῚῸῪῺἈἘἨἸὈὨᾈᾘᾨἌἜἬἼὌὬᾌᾜᾬἊἚἪἺὊὪᾊᾚᾪἎἮἾὮᾎᾞᾮἉἙἩἹὉὙὩᾉᾙᾩῬἍἝἭἽὍὝὭᾍᾝᾭἋἛἫἻὋὛὫᾋᾛᾫἏἯἿὟὯᾏᾟᾯΪΫᾹῙῩᾸῘῨ])
When the JavaScript engine is selected, the behaviour is as expected. However, if I select PCRE not only are capital letters selected, but also a bunch of seemingly random lowercase letters.
Can anyone shed some light on what is going on here? Is this a bug? Is there a way to get the desired result using the PCRE engine?
You need to tell the PCRE regex engine the input is to be parsed as a Unicode string.
In a PCRE regex, you can prepend the pattern with a (*UTF) verb. The (*UTF)[Α-ΩΗΙΟΥΩᾼῌῼΡΆΈΉΊΌΎΏᾺῈῊῚῸῪῺἈἘἨἸὈὨᾈᾘᾨἌἜἬἼὌὬᾌᾜᾬἊἚἪἺὊὪᾊᾚᾪἎἮἾὮᾎᾞᾮἉἙἩἹὉὙὩᾉᾙᾩῬἍἝἭἽὍὝὭᾍᾝᾭἋἛἫἻὋὛὫᾋᾛᾫἏἯἿὟὯᾏᾟᾯΪΫᾹῙῩᾸῘῨ] highights the correct matches.
However, you can also make it a bit shorter with
(*UTF)(?=\p{Lu})\p{Greek}
Here,
(*UTF) - a PCRE verb telling the PCRE engine the input is a Unicode string
(?=\p{Lu}) - a positive lookahead requiring the next char to be an uppercase char
\p{Greek} - a Greek char.
Note in case there is a u flag support in your PCRE implementation, it is most probably the way to go (as in PHP, /(?=\p{Lu})\p{Greek}/u).
Related
I have the following string:
https://www.google.com/today/sunday/abcde2.hopeho.3345GETD?weatherType=RAOM&...
https://www.google.com/today/monday/jbkwe3.ho4eho.8495GETD?weatherType=WHTDSG&...
I'd like to extract jbkwe3.ho4eho.8495GETD or abcde2.hopeho.3345GETD. Anything between the {weekday}/ and the ?weatherType=.
I've tried (?<=sunday\/)$.*?(?=\?weatherType=) but it only works for the first line and I want to make it applicable to all strings regardless the value of {weekday}.
I tried (?<=\/.*\/)$.*?(?=\?weatherType=) but it didn't work. Could anyone familiar with Regex can lend some help? Thank you!
[Update]
I'm new to regex but I was experimenting it on sublime text editor via the "find" functionality which I think should be PCRE (according to this post)
Try this regex:
(?:sun|mon|tues|wednes|thurs|fri|satur)day\/\K[^?]+(?=\?weatherType)
Click for Demo
Link to Code
Explanation:
(?:sun|mon|tues|wednes|thurs|fri|satur)day - matches the day of a week i.e, sunday,monday,tuesday,wednesday,thursday,friday,saturday
\/ - matches /
\K - unmatches whatever has been matched so far and pretends that the match starts from the current position. This can be used for the PCRE.
[^?]+ - matches 1 or more occurences of any character that is not a ?
(?=\?weatherType) - the above subpattern[^?]+ will match all characters that are not ? until it reaches a position which is immediately followed by a ? followed by weatherType
To make the match case-insensitive, you can prepend the regex with (?i) as shown here
In the examples given, you actually only need to grab the characters between the last forward slash ("/") and the first question mark ("?").
You didn't mention what flavor regex (ie, PCRE, grep, Oracle, etc) you're using, and the actual syntax will vary depending on this, but in general, something like the following (Perl) replacement regex would handle the examples given:
s/.*\/([^?]*)\?.*/$1/gm
There are other (and more efficient) ways, but this will do the job.
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 regex in Go to test for Latin letters only.
I know that \p{Latin} matches with any Latin script characters, but it also matches things such as Roman Numerals (e.g. "ⅻ").
That leads me to \p{L} which matches Unicode letters, but it matches any script, not just Latin.
Best I've been able to come with so far is two regexes with an &&:
latinRe := regexp.MustCompile(`\p{Latin}`)
letterRe := regexp.MustCompile(`\p{L}`)
if latinRe.Matches(testString) && letterRe.Matches(testString) {...}
I'm not happy that I can't test this as easily using something like regex101.com.
Is there a better way? More succinct? Performant?
You can use a range like the following to specify all the characters you want to match. Depending on the regex engine, one of the following should work:
See regex in use here: Adapted from this link
[A-Za-z\u00C0-\u00D6\u00D8-\u00f6\u00f8-\u00ff]
[A-Za-z\xC0-\xD6\xD8-\xf6\xf8-\xff]
Another option is to negate specific characters from a Unicode character class:
See regex in use here
[^\P{Latin}\p{N}]
I'm hoping we have some regular expression guru's here that might be able to help me - a regex newbie - solve a problem.
I know some people will want to know some background info on this issue:
Regex Flavor: Basic Regex, being used in a Vertica Database using the REGEXP_REPLACE function.
The regex I am using is working great with one exception.
I have a rule that I'm trying to implement, related to stripping the numbers from text, where any number that is part of a word, e.g. table5, go2market, 33monroe, room222, etc. is ignored and NOT filtered.
Here is what I started with for detecting numbers:
[-+]?[0-9]*\.?[0-9]
That seems to work pretty well, including handling directly adjacent commas and parentheses for example.
But all cases where there is a number that is part of alphabetic text is also being detected, which fails the rule that it cannot be a part of a word, and by word, I mean any alphabetic text.
So, in searching for solutions, I happened upon this regex that seems to work well detecting those specific cases where numbers appear next to, or in, any string of characters:
((?:[a-zA-Z]+[0-9]|[0-9]+[a-zA-Z])[a-zA-Z0-9]*)
My thought was that maybe I could add this as an INVERTED match to my original regex, to allow it to still select standalone numbers while ignoring those that were a part of a word, like so:
[-+]?[0-9]^((?:[a-zA-Z]+[0-9]|[0-9]+[a-zA-Z])[a-zA-Z0-9]*)*\.?[0-9]^((?:[a-zA-Z]+[0-9]|[0-9]+[a-zA-Z])[a-zA-Z0-9]*)
Unfortunately however, it breaks the original detection of standalone numbers.
:(
I'm hoping there is someone here that can spot what I'm doing wrong, and help me identify the right solution?
Thanks in advance!
According to Vertica documentation, the regex flavour seems to follow the Perl syntax. In this case you can use negative lookarounds and in particular a negative lookbehind: (?<!\w) (not preceded with a word character.)
Lookarounds are only tests and don't consume characters.
You can also use a negative lookahead to test the right part, (?!\w) (not followed by a word character), but it's more simple to use a word boundary since the pattern ends with a digit (that is also a word character):
(?<!\w)[-+]?\d*\.?\d+\b
In the worst case, if you have something like v1.0 in your string and you want to avoid it, you can try to use the bactracking control verbs (*SKIP) and (*FAIL). (*FAIL) forces the pattern to fail and (*SKIP) skips all the already matched positions before it. I hope vertica supports these Perl regex features.
Something like:
\p{L}+[-+]?\d*\.?\d+(*SKIP)(*FAIL)|[-+]?\d*\.?\d+(*SKIP)(?!\p{L})
I have a question:
I want to do a validation for the first and the last name with RegEx.
I want to do it with only Hebrew and English without numbers.
Someone can help me to do that code?
Seemingly Hebrew has the range \u0590-\u05fe (according to this nice JavaScript Unicode Regex generator`.
/^[a-z\u0590-\u05fe]+$/i
While the selected answer is correct about "Hebrew" the OP wanted to limit validation to only Hebrew and English letters. The Hebrew Unicode adds a lot of punctuation and symbols (as you can see in the table here) irrelevant for such validation. If you want only Hebrew letters (along with English letters) the regex would be:
/^[a-z\u05D0-\u05EA]+$/i
I would consider adding ' (single quote) as well, for foreign consonants that are missing in Hebrew (such as G in George and Ch in Charlie) make use of it along with a letter:
/^[a-z\u05D0-\u05EA']+$/i
English & Hebrew FULL regex
I'm using the above regex on my application. My users are just fine with it:
RegExp(r'^[a-zA-Z\u0590-\u05FF\u200f\u200e ]+$');
The regex supports:
English letters (includes Capital letters). a-zA-Z
Hebrew (includes special end-letters). \u0590-\u05FF
change direction unicodes (RLM, LRM). \u200f\u200e
White space.
Enjoy!
Try this. Not sure if it will work. If not, these references should help.
[A-Za-z\u0590-\u05FF]*
Hebrew Unicode
Unicode in Regular Expressions
Hebrew letters only:
/^[\u0590-\u05ea]+$/i
You can also use \p{Hebrew} in your regex to detect any Hebrew unicode characters (if you're regex engine supports it).
Well, the RegEx pattern is between two /'s. The i at the end is a flag that says to be indifferent to the cases. ^ means the start of a line, and $ means the end of a line. Brackets ([ and ]) means either of the characters inside the brackets. - means a range. Note that the characters are ordinal, so a-z or א-ת make sense; a-z means all letters from and include a to and include z. The same goes for א-ת. + means one or more of the preceding. So this pattern matches every sequence of letters from English or Hebrew.
P.S.: Also, note that the flavor of the RegEx is different in different languages and platforms. for example in Sublime Text the pattern would be: (?i)^[א-תa-z]+$.
/^[א-תa-z]+$/i