I am trying to create a registry expression that will detect the following syntax in a string:
OPEN-BRACKET > ANYTHING > PLUS-OR-MINUS > CLOSE-BRACKET
Example String: NB###-#####-#####-###[#+]
Please note that the expression could be anywhere in the string and have multiple occurrences.
I have tried [(.+)(\+|-)] which doesn't seem to work as I imagined it to do in php, but does work in rubular.com
What would the expression be to return the string *and* whether it was a plus or minus?
I'd suggest the pattern:
"(\[(.+)(\+|-)\])"
The parentheses capture the whole group, the \ escapes the [ and ] characters, and also the + character, that, otherwise (when unescaped) have special meanings in regular expressions.
Maybe .+ consumes all due to the default greedyness? What happens if you anchor the string using ^\[(.+)(\+|-)\]$.
If you cannot anchor the string due to multiply occurrences, try using look-ahead feature. And if "ANYTHING" really can be anything, how do you distinguish an ANYTHING +] from a PLUS-OR-MINUS > CLOSE-BRACKET?
If neither plus nor minus is allowed in ANYTHING, go for \[([^+-]+)(\+|-)\].
Thanks for the help. I managed to figure out /\[([\$|a-zA-Z]+)(\+|-)\]/ works as i intended it to.
Related
I have the following content in a string (query from the DB), example:
$fulltext = "Thank you so much, {gallery}art-by-stephen{/gallery}. As you know I fell in love with it from the moment I saw it and I couldn’t wait to have it in my home!"
So I only want to extract what it is between the {gallery} tags, I'm doing the following but it does not work:
$regexPatternGallery= '{gallery}([^"]*){/gallery}';
preg_match($regexPatternGallery, $fulltext, $matchesGallery);
if (!empty($matchesGallery[1])) {
echo ('<p>matchesGallery: '.$matchesGallery[1].'</p>');
}
Any suggestions?
Try this:
$regexPatternGallery= '/\{gallery\}(.*)\{\/gallery\}/';
You need to escape / and { with a \ before it. And you where missing start and end / of the pattern.
http://www.phpliveregex.com/p/fn1
Similar to Andreas answer but differ in ([^"]*?)
$regexPatternGallery= '/\{gallery\}([^"]*?)\{\/gallery\}/';
Don't forget to put / at the beginning and the end of the Regex string. That's a must in PHP, different from other programming languages.
{,},/ are characters that can be confused as a Regex logic, so you have to escape it using \ like \{.
Use ? to make the string to non-greedy, thus saves memory. It avoids error when facing this kind of string "blabla {galery}you should only get this{/gallery} but you also got this instead.{/gallery} Rarely happens but be careful anyway".
Try this RegEx:
\{gallery\}(.*?)\{\/gallery\}
The problem with your RegEx was that you did not escape the / in the closing {gallery}. You also need to escape { and }.
You should use .*? for a lazy match, otherwise if there are 2 tags in one string, it will combine them. I.e. {gallery}by-joe{/gallery} and {gallery}by-tim{/gallery} would end up as:
by-joe{/gallery} and {gallery}by-tim
However, using a lazy match, you would get 2 results:
by-joe
by-tim
Live Demo on Regex101
I am stuck trying to create a regex that will allow for letters, numbers, and the following chars: _ - ! ? . ,
Here is what I have so far:
/^[-\'a-zA-Z0-9_!\?,.\s]+$/ //not escaping the ?
and this version too:
/^[-\'a-zA-Z0-9_!\?,.\s]+$/ //attempting to escape the ?
Neither of these seem to be able to match the following:
"Oh why, oh why is this regex not working! It's getting pretty frustrating? Frustrating - that is to say the least. Hey look, an underscore_ I wonder if it will match this time around?"
Can somebody point out what I am doing wrong? I must point out that my script takes the user input (the paragraph in quotes in this case) and strips all white space so actual input has no white space.
Thanks!
UPDATE:
Thanks to Lix's advice, this is what I have so far:
/^[-\'a-zA-Z0-9_!\?,\.\s]+$/
However, it's still not working??
UPDATE2
Ok, based on input this is what's happening.
User inputs string, then I run the string through following functions:
$comment = preg_replace('/\s+/', '',
htmlspecialchars(strip_tags(trim($user_comment_orig))));
So in the end, user input is just a long string of chars without any spaces. Then that string of chars is run using:
preg_match("#^[-_!?.,a-zA-Z0-9]+$#",$comment)
What could possibly be causing trouble here?
FINAL UPDATE:
Ended up using this regex:
"#[-'A-Z0-9_?!,.]+#i"
Thanks all! lol, ya'll are going to kill me once you find out where my mistake was!
Ok, so I had this piece of code:
if(!preg_match($pattern,$comment) || strlen($comment) < 2 || strlen($comment) > 60){
GEEZ!!! I never bothered to look at the strlen part of the code. Of course it was going to fail every time...I only allowed 60 chars!!!!
When in doubt, it's always safe to escape non alphanumeric characters in a class for matching, so the following is fine:
/^[\-\'a-zA-Z0-9\_\!\?\,\.\s]+$/
When run through a regular expression tester, this finds a match with your target just fine, so I would suggest you may have a problem elsewhere if that doesn't take care of everything.
I assume you're not including the quotes you used around the target when actually trying for a match? Since you didn't build double quote matching in...
Can somebody point out what I am doing wrong? I must point out that my script takes the user input (the paragraph in quotes in this case) and strips all white space so actual input has no white space.
in which case you don't need the \s if it's working correctly.
I got the following code to work as expected to (running php5):
<?php
$pattern = "#[-'A-Z0-9_?!,.\s]+#i";
$string = "Oh why, oh why is this regex not working! It's getting pretty frustrating? Frustrating - that is to say the least. Hey look, an underscore_ I wonder if it will match this time around?";
$results = array();
preg_match($pattern, $string, $results);
echo '<pre>';
print_r($results);
echo '</pre>';
?>
The output from print_r($results) was as following:
Array
(
[0] => Oh why, oh why is this regex not working! It's getting pretty frustrating? Frustrating - that is to say the least. Hey look, an underscore_ I wonder if it will match this time around?
)
Tested on http://writecodeonline.com/php/.
It's not necessary to escape most characters inside []. However, \s will not do what you want inside the expression. You have two options: either manually expand (/^[-\'a-zA-Z0-9_!?,. \t\n\r]+$/) or use alternation (/^(?:[-\'a-zA-Z0-9_!?,.]|\s)+$/).
Note that I left the \ before the ' because I'm assuming you're putting this in a PHP string and I wouldn't want to suggest a syntax error.
The only characters with a special meaning within a character class are:
the dash (since it can be used as a delimiter for ranges), except if it is used at the beginning (since in this case it is no part of any range),
the closing bracket,
the backslash.
In "pure regex parlance", your character class can be written as:
[-_!?.,a-zA-Z0-9\s]
Now, you need to escape whatever needs to be escaped according to your language and how strings are written. Given that this is PHP, you can take the above sample as is. Note that \s is interpreted in character classes as well, so this will match anything which is matched by \s outside of a character class.
While some manuals recommend using escapes for safety, knowing the general regex rules for character classes and applying them leads to shorter and easier to read results ;)
I've created a regular expression: ^\\[(.*)\\]$
to find all strings [....] eg. [general]
and I need to replace it with ['general']
but it is not working
in Netbeans php also I need lowercase like general_offline
Thanks
I see two things that would probably make problems
You used the anchors ^ and $. they match the start and the end of the string, if you are searching inside a larger text it will not find them. If so, just remove them:
\\[(.*)\\]
.* is greedy. That means \\[(.*)\\] will match from the frist opening [ to the last closing ]. If so add a ? after the quantifier to change the matching behaviour to "lazy".
\\[(.*?)\\]
See it here on Regexr
Strange this one works: (\[.*]) almost because I need to find inside without [ ]
This is the text sample:
$text = "asd dasjfd fdsfsd http://11111.com/asdasd/?s=423%423%2F gfsdf http://22222.com/asdasd/?s=423%423%2F
asdfggasd http://3333333.com/asdasd/?s=423%423%2F";
This is my regex pattern:
preg_match_all( "#http:\/\/(.*?)[\s|\n]#is", $text, $m );
That match the first two urls, but how do I match the last one? I tried adding [\s|\n|$] but that will also only match the first two urls.
Don't try to match \n (there's no line break after all!) and instead use $ (which will match to the end of the string).
Edit:
I'd love to hear why my initial idea doesn't work, so in case you know it, let me know. I'd guess because [] tries to match one character, while end of line isn't one? :)
This one will work:
preg_match_all('#http://(\S+)#is', $text, $m);
Note that you don't have to escape the / due to them not being the delimiting character, but you'd have to escape the \ as you're using double quotes (so the string is parsed). Instead I used single quotes for this.
I'm not familar with PHP, so I don't have the exact syntax, but maybe this will give you something to try. the [] means a character class so |$ will literally look for a $. I think what you'll need is another look ahead so something like this:
#http:\/\/(.*)(?=(\s|$))
I apologize if this is way off, but maybe it will give you another angle to try.
See What is the best regular expression to check if a string is a valid URL?
It has some very long regular expressions that will match all urls.
I found a regex pattern for PHP that does the exact OPPOSITE of what I'm needing, and I'm wondering how I can reverse it?
Let's say I have the following text: Item_154 ($12)
This pattern /\((.*?)\)/ gets what's inside the parenthesis, but I need to get "Item_154" and cut out what's in parenthesis and the space before the parenthesis.
Anybody know how I can do that?
Regex is above my head apparently...
/^([^( ]*)/
Match everything from the start of the string until the first space or (.
If the item you need to match can have spaces in it, and you only want to get rid of whitespace immediately before the parenthetical, then you can use this instead:
/^([^(]*?)\s*\(/
The following will match anything that looks like text (...) but returns just the text part in the match.
\w+(?=\s*\([^)]*\))
Explanation:
The \w includes alphanumeric and underscore, with + saying match one or more.
The (?= ) group is positive lookahead, saying "confirm this exists but don't match it".
Then we have \s for whitespace, and * saying zero or more.
The \( and \) matches literal ( and ) characters (since its normally a special chat).
The [^)] is anything non-) character, and again * is zero or more.
Hopefully all makes sense?
/(.*)\(.*\)/
What is not in () will now be your 1st match :)
One site that really helped me was http://gskinner.com/RegExr/
It'll let you build a regex and then paste in some sample targets/text to test it against, highlighting matches. All of the possible regex components are listed on the right with (essentially) a tooltip describing the function.
<?php
$string = 'Item_154 ($12)';
$pattern = '/(.*)\(.*?\)/';
preg_match($pattern, $string, $matches);
var_dump($matches[1]);
?>
Should get you Item_154
The following regex works for your string as a replacement if that helps? :-
\s*\(.*?\)
Here's an explanation of what's it doing...
Whitespace, any number of repetitions - \s*
Literal - \(
Any character, any number of repetitions, as few as possible - .*?
Literal - \)
I've found Expresso (http://www.ultrapico.com/) is the best way of learning/working out regular expressions.
HTH
Here is a one-shot to do the whole thing
$text = 'Item_154 ($12)';
$text = preg_replace('/([^\s]*)\s(\()[^)]*(\))/', $1$2$3, $text);
var_dump($text);
//Outputs: Item_154()
Keep in mind that using any PCRE functions involves a fair amount of overhead, so if you are using something like this in a long loop and the text is simple, you could probably do something like this with substr/strpos and then concat the parens on to the end since you know that they should be empty anyway.
That said, if you are looking to learn REGEXs and be productive with them, I would suggest checking out: http://rexv.org
I've found the PCRE tool there to very useful, though it can be quirky in certain ways. In particular, any examples that you work with there should only use single quotes if possible, as it doesn't work with double quotes correctly.
Also, to really get a grip on how to use regexs, I would check out Mastering Regular Expressions by Jeffrey Friedl ISBN-13:978-0596528126
Since you are using PHP, I would try to get the 3rd Edition since it has a section specifically on PHP PCRE. Just make sure to read the first 6 chapters first since they give you the foundation needed to work with the material in that particular chapter. If you see the 2nd Edition on the cheap somewhere, that pretty much the same core material, so it would be a good buy as well.