I'm trying to use regular expression to match hashtags. When the language of a hashtag is English or Chinese, my code works fine. But when the language is Bengali, my code can't match the whole Bengali word.
Here is the code I'm testing with:
<?php
$hashtag = '#আয়াতুল_কুরসি';
preg_match('/(#\w+)/u', $hashtag, $matches);
print_r($matches);
?>
And the result is:
Array
(
[0] => #আয়
[1] => #আয়
)
I tried changing the pattern to '/(#\p{L}+)/u', but that didn't help.
The fact is that \w here does not match all diacritics that Bengali characters may contain. You need to allow them all:
preg_match('/#[\w\p{M}]+/u', $hashtag, $matches);
See the PHP demo.
Related
The first question is this:
I am using http://www.phpliveregex.com/ to check my regex is right and it finds more than one matching lines.
I am doing this regex:
$lines = explode('\n', $text);
foreach($lines as $line) {
$matches = [];
preg_match("/[0-9]+[A-Z][a-z]+ [A-Z][a-z]+S[0-9]+\-[0-9]+T[0-9]+/uim", $line, $matches);
print_r($matches);
}
on the $text which looks like this: http://pastebin.com/9UQ5wNRu
The problem is that printed matches is only one match:
Array
(
[0] => 3Bajus StanislavS2415079249-2615T01
)
Why is it doing to me? any ideas what could fix the problem?
The second question
Maybe you've noticed not regular alphabetic characters of slovak language inside the text (from pastebin). How to match those characters and select the users which have this format:
{number}{first_name}{space}{last_name}{id_number}
how to do that?
Ok first issue is fixed. Thank you #chris85 . I should have used preg_match_all and do it on the whole text. Now I get an array of all students which have non-slovak (english) letters in the name.
preg_match is for one match. You need to use preg_match_all for a global search.
[A-Z] does not include an characters outside that range. Since you are using the i modifier that character class actual is [A-Za-z] which may or may not be what you want. You can use \p{L} in place of that for characters from any language.
Demo: https://regex101.com/r/L5g3C9/1
So your PHP code just be:
preg_match_all("/^[0-9]+\p{L}+ \p{L}+S[0-9]+\-[0-9]+T[0-9]+$/uim", $text, $matches);
print_r($matches);
You can also use T-Regx library:
pattern("^[0-9]+\p{L}+ \p{L}+S[0-9]+\-[0-9]+T[0-9]+$", 'uim')->match($text)->all();
I'm going to be working with a long string of data that is serialized into blocks using a pattern (x:y).
However, I struggle with regular expressions, and are looking for resources to help identify how to construct a regex to identify any/all of these blocks as they appear in a string.
For example, given the following string:
$s = 't:user c:red t:admin n:"bob doe" s:expressionsf:json';
Note: the f:json at the end is missing a space on purpose, because the format might vary with how the string is eventually given to me. Each block might be spaced, and they might not.
How would I identify each block of x:y to end with the below result:
Array
(
[0] => t:user
[1] => c:red
[2] => t:admin
[3] => n:"bob doe"
[4] => s:expression
[5] => f:json
)
I've tested various expressions using my limited knowledge, but have not been terribly successful.
I can successfully match the pattern using something like this:
^[ctrns]:.+
But this unfourtunately matches the entire string. The part I seem to be missing is how to break each block, while also maintaining the ability to keep spaces within the pairs (see n:"bob doe" example).
Any assistance would be super appreciated! Also, ideally any submission would be explained as to what each token in the expression was accomplishing so that I better my understanding of these techniques.
I've been using https://regexr.com/ to practice.
You may use this regex in preg_match_all:
[ctnsf]:(?:"[^"\\]*(?:\\.[^"\\]*)*"|\S+?(?=[ctnsf]:|\s|$))
RegEx Demo
RegEx Details:
[ctnsf]:: Match one of ctnsf characters followed by :
(?:"[^"\\]*(?:\\.[^"\\]*)*": Match a quoted substring. This takes care of escaped quotes as well.
|: OR
\S+?: Match 1+ not-whitespace characters (non-greedy)
(?=[ctnsf]:|\s|$): Positive lookahead to assert one of the conditions given in assertions.
Code:
$re = '/[ctnsf]:(?:"[^"\\\\]*(?:\\\\.[^"\\\\]*)*"|\S+?(?=[ctnsf]:|\s|$))/m';
$str = 't:user c:red t:admin n:"bob \\"doe" s:expressionsf:json';
preg_match_all($re, $str, $matches);
// Print the entire match result
print_r($matches[0]);
Code Demo
The first question is this:
I am using http://www.phpliveregex.com/ to check my regex is right and it finds more than one matching lines.
I am doing this regex:
$lines = explode('\n', $text);
foreach($lines as $line) {
$matches = [];
preg_match("/[0-9]+[A-Z][a-z]+ [A-Z][a-z]+S[0-9]+\-[0-9]+T[0-9]+/uim", $line, $matches);
print_r($matches);
}
on the $text which looks like this: http://pastebin.com/9UQ5wNRu
The problem is that printed matches is only one match:
Array
(
[0] => 3Bajus StanislavS2415079249-2615T01
)
Why is it doing to me? any ideas what could fix the problem?
The second question
Maybe you've noticed not regular alphabetic characters of slovak language inside the text (from pastebin). How to match those characters and select the users which have this format:
{number}{first_name}{space}{last_name}{id_number}
how to do that?
Ok first issue is fixed. Thank you #chris85 . I should have used preg_match_all and do it on the whole text. Now I get an array of all students which have non-slovak (english) letters in the name.
preg_match is for one match. You need to use preg_match_all for a global search.
[A-Z] does not include an characters outside that range. Since you are using the i modifier that character class actual is [A-Za-z] which may or may not be what you want. You can use \p{L} in place of that for characters from any language.
Demo: https://regex101.com/r/L5g3C9/1
So your PHP code just be:
preg_match_all("/^[0-9]+\p{L}+ \p{L}+S[0-9]+\-[0-9]+T[0-9]+$/uim", $text, $matches);
print_r($matches);
You can also use T-Regx library:
pattern("^[0-9]+\p{L}+ \p{L}+S[0-9]+\-[0-9]+T[0-9]+$", 'uim')->match($text)->all();
I have a special tag in text [Attachment: image;upload;url] to parse it I need to find all this tags, I have wrote this regular expression:
preg_match_all("/.*(\[Attachment: (.*);upload;(.*)\]).*/", $text, $matches);
All work fine, it returns this
Array
(
[0] => Array
(
Text
)
[1] => Array
(
[Attachment: image;upload;url]
)
[2] => Array
(
image
)
[3] => Array
(
url
)
)
But here is one problem, when text contains two or more tags, it will return info only about last founded tag.
You should match only the tags, not the surrounding text:
"/\[Attachment: ([^;]*);upload;([^\]]*)\]/"
Instead of the negative character set you could also use .*? to use non-greedy matching; however, I prefer to use the look-ahead set.
Remove the .* part from the end of the regex. With the .*, the regex matches to the end of the string, including any of the other substrings that you want to find. (Or at least all the ones on the same line - I can't remember what the default settings are in PHP.) After that it looks for more matches from the end of the string, but can't find any.
This regex should do it:
$regex = '/[Attachment: (.*?);(.*?);(.*?)]/';
preg_match_all($regex, $string, $matches);
For me, this came back with what you wanted (3 results);
I have a problem with a regex I wrote to match shortcodes in PHP.
This is the pattern, where $shortcode is the name of the shortcode:
\[$shortcode(.+?)?\](?:(.+?)?\[\/$shortcode\])?
Now, this regex behaves pretty much fine with these formats:
[shortcode]
[shortcode=value]
[shortcode key=value]
[shortcode=value]Text[/shortcode]
[shortcode key1=value1 key2=value2]Text[shortcode]
But it seems to have problems with the most common format,
[shortcode]Text[/shortcode]
which returns as matches the following:
Array
(
[0] => [shortcode]Text[/shortcode]
[1] => ]Text[/shortcode
)
As you can see, the second match (which should be the text, as the first is optional) includes the end of the opening tag and all the closing tag but the last bracket.
EDIT: Found out that the match returned is the first capture, not the second. See the regex in Regexr.
Can you help with this please? I'm really crushing my head on this one.
In your regex:
\[$shortcode(.+?)?\](?:(.+?)?\[\/$shortcode\])?
The first capture group (.+?) matches at least 1 character.
The whole group is optional, but in this case it happens to match every thing up to the last ].
The following regex works:
\[$shortcode(.*?)?\](?:(.+?)?\[\/$shortcode\])?
The * quantifier means 0 or more, while + means one or more.
Granted this is from C#, but
#"\[([\w-_]+)([^\]]*)?\](?:(.+?)?\[\/\1\])?"
should match any (?) possibly self-closing shortcode.
Or you could steal from wordpress: https://core.trac.wordpress.org/browser/tags/4.0/src/wp-includes/shortcodes.php#L309
$pattern = '/(\w+)\s*=\s*"([^"]*)"(?:\s|$)|(\w+)\s*=\s*\'([^\']*)\'(?:\s|$)|(\w+)\s*=\s*([^\s\'"]+)(?:\s|$)|"([^"]*)"(?:\s|$)|(\S+)(?:\s|$)/';
$text = preg_replace("/[\x{00a0}\x{200b}]+/u", " ", $text);
if ( preg_match_all($pattern, $text, $match, PREG_SET_ORDER) )...