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preg_replace
preg_replace & Sucht und ersetzt mit regul?ren Ausdrücken
Beschreibung
preg_replace
$replacement
[, int $limit = -1
[, int &$count
Parameter-Liste
Der Ausdruck, nach dem gesucht wird. Es kann entweder eine Zeichenkette
oder ein Array mit Zeichenketten sein.
Es stehen auch einige
zur Verfügung.
replacement
Die Zeichenkette oder das Array mit Zeichenketten zum Ersetzen. Falls
dieser Parameter eine Zeichenkette ist und der Parameter
pattern ein Array, werden alle Suchmuster durch
diese Zeichenkette ersetzt. Falls sowohl pattern
als auch replacement Arrays sind, wird jedes
Suchmuster pattern durch das Gegenstück aus
replacement ersetzt. Wenn das
replacement-Array weniger Elemente hat als das
pattern-Array, wird jedes überz?hlige
pattern durch die leere Zeichenkette ersetzt.
replacement darf Referenzen in der Form
\\n oder (ab PHP 4.0.4)
$n enthalten, wobei
Letztere vorzuziehen ist. Jede dieser Referenzen wird mit dem Text
ersetzt, der vom n-ten eingeklammerten
Suchmuster erfasst wurde. n kann einen Wert
von 0 bis 99 haben. \\0 oder $0
beziehen sich auf den Text, der auf das komplette Suchmuster passt. Um
die Nummer des erfassenden Teil-Suchmusters zu erhalten, werden
?ffnende Klammern mit 1 beginnend von links nach rechts gez?hlt. Um
einen Backslash im Ersatz zu verwenden, muss er verdoppelt werden
(&\\\\& PHP-Zeichenkette).
Wenn Sie mit einer Ersetzung arbeiten wollen, in der auf eine
Rückreferenzierung direkt eine weitere Zahl folgt (d.h., direkt nach
der ?bereinstimmmung mit einem Suchmuster soll eine Zahl kommen),
k?nnen Sie für Ihre Rückreferenzierung nicht die Schreibweise
\\1 verwenden. So würde z.B. \\11
die Funktion preg_replace() verwirren, weil sie
nicht weiss, ob Sie die Rückreferenzierung \\1
gefolgt von der Zahl 1 wollen oder nur die
Rückreferenzierung \\11. In diesem Fall ist die
L?sung, \${1}1 zu verwenden. Damit wird eine
isolierte Rückreferenzierung $1 erzeugt und die
1 bleibt ein Buchstabensymbol.
Wenn Sie den veralteten Modifikator e verwenden,
maskiert diese Funktion ein paar Zeichen (n?mlich ',
&, \ und NULL) in den
Zeichenketten, mit denen die Rückreferenzierungen ersetzen werden. Das
wird gemacht, um sicherzustellen, dass keine Syntaxfehler entstehen,
wenn Rückreferenzierungen verwendet werden, die einfache oder doppelte
Anführungszeichen enthalten (z.B.
'strlen(\'$1\')+strlen(&$2&)'). Vergewissern Sie
sich, dass Sie die
kennen, um genau zu wissen, wie die ausgewertete Zeichenkette aussieht.
Die Zeichenkette oder ein Array mit Zeichenketten zum Durchsuchen.
Falls subject ein Array ist, wird das Suchen und
Ersetzen auf jedes Element von subject angewandt
und der Rückgabewert ist ebenfalls ein Array.
Die maximal m?gliche Anzahl von Ersetzungen für jedes Suchmuster in
jeder subject. Standardm?ssiger Wert:
-1 (kein Limit).
Falls angegeben, wird dieser Variable die Anzahl vorgenommener
Ersetzungen zugewiesen.
Rückgabewerte
preg_replace() gibt ein Array zurück, falls
subject ein Array ist, andernfalls eine
Zeichenkette.
Falls ?bereinstimmungen gefunden wurden, wird die neue Zeichenkette
subject zurückgegeben, andernfalls wird
subject unver?ndert zurückgegeben oder NULL, falls
ein Fehler auftrat.
Fehler/Exceptions
Ab PHP 5.5.0 wird bei ?bergabe des Modifikators &\e& ein Fehler der Stufe
E_DEPRECATED ausgegeben. Ab PHP 7.0.0 wird in diesem
Fall ein Fehler der Stufe E_WARNING ausgegeben, und der
&\e& Modifikator hat keine Wirkung.
Beispiel #1
Die Verwendung von Rückreferenzierungen mit darauf folgenden numerischen
&?php$zeichenkette&=&'15.&April&2003';$suchmuster&=&'/(\d+)\.&(\w+)&(\d+)/i';$ersetzung&=&'${2}1,$3';echo&preg_replace($suchmuster,&$ersetzung,&$zeichenkette);?&
Das oben gezeigte Beispiel erzeugt folgende
April1,2003
Beispiel #2
Die Verwendung von preg_replace() mit indizierten
&?php$zeichenkette&=&'Der&schnelle&braune&Fuchs&sprang&über&den&faulen&Hund.';$suchmuster&=&array();$suchmuster[0]&=&'/schnelle/';$suchmuster[1]&=&'/braune/';$suchmuster[2]&=&'/Fuchs/';$ersetzungen&=&array();$ersetzungen[2]&=&'B?r';$ersetzungen[1]&=&'schwarze';$ersetzungen[0]&=&'langsame';echo&preg_replace($suchmuster,&$ersetzungen,&$zeichenkette);?&
Das oben gezeigte Beispiel erzeugt folgende
Der B?r schwarze langsame sprang über den faulen Hund.
Wenn wir Suchmuster und Ersetzungen mit
sortieren, sollten wir bekommen was wir wollten.
&?phpksort($suchmuster);ksort($ersetzungen);echo&preg_replace($suchmuster,&$ersetzungen,&$zeichenkette);?&
Das oben gezeigte Beispiel erzeugt folgende
Der langsame schwarze B?r sprang über den faulen Hund.
Beispiel #3 Ersetzen mehrerer Werte
&?php$suchmuster&=&array&('/(19|20)(\d{2})-(\d{1,2})-(\d{1,2})/',&&&&&&&&&&&&&&&&&&&&&'/^\s*{(\w+)}\s*=/');$ersetzen&=&array&('\4.\3.\1\2',&'$\1&=');echo&preg_replace($suchmuster,&$ersetzen,&'{startDatum}&=&');?&
Das oben gezeigte Beispiel erzeugt folgende
$startDatum = 27.5.1999
Beispiel #4 Leerzeichen entfernen
Dieses Beispiel entfernt überschüssige Leerzeichen aus einer
Zeichenkette.
&?php$str&=&'foo&&&o';$str&=&preg_replace('/\s\s+/',&'&',&$str);//&Das&ist&jetzt&'foo&o'echo&$str;?&
Beispiel #5 Die Verwendung des Parameters count
&?php$anzahl&=&0;echo&preg_replace(array('/\d/',&'/\s/'),&'*',&'xp&4&to',&-1&,&$anzahl);echo&$anzahl;&//3?&
Das oben gezeigte Beispiel erzeugt folgende
Anmerkungen
Bei Verwendung von Arrays für pattern und
replacement werden die Schlüssel in der Reihenfolge
bearbeitet, in der sie im Array vorliegen. Das ist nicht
notwendigerweise dieselbe, wie die numerische Reihenfolge der
Indizes. Wenn Sie Indizes verwenden, um festzulegen welches
pattern durch welchen Ersatz
replacement ersetzt werden soll, sollten Sie vor
dem Aufruf von preg_replace()
auf jedes Array anwenden.
Siehe auch
- Maskiert Zeichen regul&rer Ausdr&cke
- Sucht und ersetzt mit regul&ren Ausdr&cken
- F&hrt eine Suche mit einem regul&ren Ausdruck durch
- F&hrt eine Suche mit einem regul&ren Ausdruck durch und ersetzt mittels eines Callbacks
- Zerlegt eine Zeichenkette anhand eines regul&ren Ausdrucks
- Liefert den Fehlercode der letzten PCRE RegEx-Auswertung
Because i search a lot 4 this:The following should be escaped if you are trying to match that character\ ^ . $ | ( ) [ ]* + ? { } ,Special Character Definitions\ Quote the next metacharacter^ Match the beginning of the line. Match any character (except newline)$ Match the end of the line (or before newline at the end)| Alternation() Grouping[] Character class* Match 0 or more times+ Match 1 or more times? Match 1 or 0 times{n} Match exactly n times{n,} Match at least n times{n,m} Match at least n but not more than m timesMore Special Character Stuff\t tab (HT, TAB)\n newline (LF, NL)\r return (CR)\f form feed (FF)\a alarm (bell) (BEL)\e escape (think troff) (ESC)\033 octal char (think of a PDP-11)\x1B hex char\c[ control char\l lowercase next char (think vi)\u uppercase next char (think vi)\L lowercase till \E (think vi)\U uppercase till \E (think vi)\E end case modification (think vi)\Q quote (disable) pattern metacharacters till \EEven More Special Characters\w Match a "word" character (alphanumeric plus "_")\W Match a non-word character\s Match a whitespace character\S Match a non-whitespace character\d Match a digit character\D Match a non-digit character\b Match a word boundary\B Match a non-(word boundary)\A Match only at beginning of string\Z Match only at end of string, or before newline at the end\z Match only at end of string\G Match only where previous m//g left off (works only with /g)
If you want to catch characters, as well european, russian, chinese, japanese, korean of whatever, just :- use mb_internal_encoding('UTF-8');- use preg_replace('`...`u', '...', $string) with the u (unicode) modifierFor further information, the complete list of preg_* modifiers could be found at :
If you have issues where preg_replace returns an empty string, please take a look at these two ini parameters:pcre.backtrack_limitpcre.recursion_limitThe default is set to 100K.& If your buffer is larger than this, look to increase these two values.
Post slug generator, for creating clean urls from titles.
It works with many languages.
&?php
function remove_accent($str)
{
& $a = array('?', '?', '?', '?', '?', '?', 'AE', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', 'ss', 'à', 'á', '?', '?', '?', '?', 'ae', '?', 'è', 'é', 'ê', '?', 'ì', 'í', '?', '?', '?', 'ò', 'ó', '?', '?', '?', '?', 'ù', 'ú', '?', 'ü', '?', '?', '?', 'ā', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', 'ē', '?', '?', '?', '?', '?', '?', '?', 'ě', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', 'ī', '?', '?', '?', '?', '?', '?', 'IJ', 'ij', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', 'ń', '?', '?', '?', 'ň', ''n', '?', 'ō', '?', '?', '?', '?', 'OE', 'oe', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', 'ū', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', 's', '?', '?', '?', '?', '?', '?', 'ǎ', '?', 'ǐ', '?', 'ǒ', '?', 'ǔ', '?', 'ǖ', '?', 'ǘ', '?', 'ǚ', '?', 'ǜ', '?', '?', '?', '?', '?', '?');
& $b = array('A', 'A', 'A', 'A', 'A', 'A', 'AE', 'C', 'E', 'E', 'E', 'E', 'I', 'I', 'I', 'I', 'D', 'N', 'O', 'O', 'O', 'O', 'O', 'O', 'U', 'U', 'U', 'U', 'Y', 's', 'a', 'a', 'a', 'a', 'a', 'a', 'ae', 'c', 'e', 'e', 'e', 'e', 'i', 'i', 'i', 'i', 'n', 'o', 'o', 'o', 'o', 'o', 'o', 'u', 'u', 'u', 'u', 'y', 'y', 'A', 'a', 'A', 'a', 'A', 'a', 'C', 'c', 'C', 'c', 'C', 'c', 'C', 'c', 'D', 'd', 'D', 'd', 'E', 'e', 'E', 'e', 'E', 'e', 'E', 'e', 'E', 'e', 'G', 'g', 'G', 'g', 'G', 'g', 'G', 'g', 'H', 'h', 'H', 'h', 'I', 'i', 'I', 'i', 'I', 'i', 'I', 'i', 'I', 'i', 'IJ', 'ij', 'J', 'j', 'K', 'k', 'L', 'l', 'L', 'l', 'L', 'l', 'L', 'l', 'l', 'l', 'N', 'n', 'N', 'n', 'N', 'n', 'n', 'O', 'o', 'O', 'o', 'O', 'o', 'OE', 'oe', 'R', 'r', 'R', 'r', 'R', 'r', 'S', 's', 'S', 's', 'S', 's', 'S', 's', 'T', 't', 'T', 't', 'T', 't', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'W', 'w', 'Y', 'y', 'Y', 'Z', 'z', 'Z', 'z', 'Z', 'z', 's', 'f', 'O', 'o', 'U', 'u', 'A', 'a', 'I', 'i', 'O', 'o', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'U', 'u', 'A', 'a', 'AE', 'ae', 'O', 'o');
& return str_replace($a, $b, $str);
}
function post_slug($str)
{
& return strtolower(preg_replace(array('/[^a-zA-Z0-9 -]/', '/[ -]+/', '/^-|-$/'),
& array('', '-', ''), remove_accent($str)));
}
?&
Example: post_slug(' -Lo#&@rem& IPSUM //dolor-/sit - amet-/-consectetur! 12 -- ')
will output: lorem-ipsum-dolor-sit-amet-consectetur-12
There seems to be some unexpected behavior when using the /m modifier when the line terminators are win32 or mac format.If you have a string like below, and try to replace dots, the regex won't replace correctly:&?php$s = "Testing, testing.\r\n"&& . "Another testing line.\r\n"&& . "Testing almost done.";echo preg_replace('/\.$/m', '.@', $s); ?&The /m modifier doesn't seem to work properly when CRLFs or CRs are used. Make sure to convert line endings to LFs (*nix format) in your input string.
preg_replace (and other preg-functions) return null instead of a string when encountering problems you probably did not think about!-------------------------It may not be obvious to everybody that the function returns NULL if an error of any kind occurres. An error I happen to stumple about quite often was the back-tracking-limit:#ini.pcre.backtrack-limitWhen working with HTML-documents and their parsing it happens that you encounter documents that have a length of over 100.000 characters and that may lead to certain regular-expressions to fail due the back-tracking-limit of above.A regular-expression that is ungreedy ("U", ) often does the job, but still: sometimes you just need a greedy regular expression working on long strings ...Since, an unhandled return-value of NULL usually creates a consecutive error in the application with unwanted and unforeseen consequences, I found the following solution to be quite helpful and at least save the application from crashing:&?php$string_after = preg_replace( '/some_regexp/', "replacement", $string_before );if (PREG_NO_ERROR !== preg_last_error()){& & $string_after = $string_before;& & & & } unset( $string_before );?&You may or should also put a log-message or the sending of an email into the if-condition in order to get informed, once, one of your regular-expressions does not have the effect you desired it to have.
If you want to replace only the n-th occurrence of $pattern, you can use this function:&?phpfunction preg_replace_nth($pattern, $replacement, $subject, $nth=1) {& & return preg_replace_callback($pattern,& & & & function($found) use (&$pattern, &$replacement, &$nth) {& & & & & & & & $nth--;& & & & & & & & if ($nth==0) return preg_replace($pattern, $replacement, reset($found) );& & & & & & & & return reset($found);& & & & }, $subject,$nth& );}echo preg_replace_nth("/(\w+)\|/", '${1} is the 4th|', "|aa|b|cc|dd|e|ff|gg|kkk|", 4);?&this outputs |aa|b|cc|dd is the 4th|e|ff|gg|kkk| backreferences are accepted in $replacement
A variable can handle a huge quantity of data but preg_replace can't.Example :&?php$url = "ANY URL WITH LOTS OF DATA";$data = file_get_contents($url);$head = preg_replace("#(.*)&head&(.*?)&/head&(.*)#is", '$2', $data);?&$head can have the desired content, or be empty, depends on the length of $data.For this application, just add :$data = substr($data, 0, 4096);before using preg_replace, and it will work fine.
Please see Example #4 Strip whitespace.& This works as designed, but if you are using Windows, it may not work as expected.& The potential "gotcha" is the CR/LF line endings.& On a Unix system, where there is only a single character line ending, that regex pattern will preserve line endings.& On Windows, it may strip line endings.
To covert a string to SEO friendly, do this:
&?php
$realname = "This is the string to be made SEO friendly!"
$seoname = preg_replace('/\%/',' percentage',$realname);
$seoname = preg_replace('/\@/',' at ',$seoname);
$seoname = preg_replace('/\&/',' and ',$seoname);
$seoname = preg_replace('/\s[\s]+/','-',$seoname);& & $seoname = preg_replace('/[\s\W]+/','-',$seoname);& & $seoname = preg_replace('/^[\-]+/','',$seoname); $seoname = preg_replace('/[\-]+$/','',$seoname); $seoname = strtolower($seoname);
echo $seoname;
?&
This will print: this-is-the-string-to-be-made-seo-friendly
Below is a function for converting Hebrew final characters to theirnormal equivelants should they appear in the middle of a word.The /b argument does not treat Hebrew letters as part of a word,so I had to work around that limitation.&?php$text="????? ???????";function hebrewNotWordEndSwitch ($from, $to, $text) {&& $text=& & preg_replace('/'.$from.'([?-?])/u','$2'.$to.'$1',$text);&& return $text;}do {&& $text_before=$text;&& $text=hebrewNotWordEndSwitch("?","?",$text);&& $text=hebrewNotWordEndSwitch("?","?",$text);&& $text=hebrewNotWordEndSwitch("?","?",$text);&& $text=hebrewNotWordEndSwitch("?","?",$text);&& $text=hebrewNotWordEndSwitch("?","?",$text);}&& while ( $text_before!=$text );print $text; ?&The do-while is necessary for multiple instances of letters, suchas "????" which would start off as "????". Note that there's still theproblem of acronyms with gershiim but that's not a difficult oneto solve. The code is in use at
which you canuse to translate wrongly-encoded Hebrew, transliterize, and someother Hebrew-related functions.To ensure that there will be no regular characters at the end of aword, just convert all regular characters to their final forms, thenrun this function. Enjoy!
If there's a chance your replacement text contains any strings such as "$0.95", you'll need to escape those $n backreferences:&?phpfunction escape_backreference($x){& & return preg_replace('/\$(\d)/', '\\\$$1', $x);}?&
Warning: a common made mistake in trying to remove all characters except numbers and letters from a string, is to use code with a regex similar to preg_replace('[^A-Za-z0-9_]', '', ...). The output goes in an unexpected direction in case your input contains two double quotes.echo preg_replace('[^A-Za-z0-9_]', '', 'D"usseldorfer H"auptstrasse')D"usseldorfer H"auptstrasseIt is important to not forget a leading an trailing forward slash in the regex: echo preg_replace('/[^A-Za-z0-9_]/', '', 'D"usseldorfer H"auptstrasse')Dusseldorfer HauptstrassePS An alternative is to use preg_replace('/\W/', '', $t) for keeping all alpha numeric characters including underscores.
I use this to prevent users from overdoing repeated text. The following function only allows 3 identical characters at a time and also takes care of repetitions with whitespace added.This means that 'haaaaaaleluuuujaaaaa' becomes 'haaaleluuujaaa' and 'I am c o o o o o o l' becomes 'I am c o o o l'&?php$str = "aaaaaaaaaaabbccccccccaaaaad d d d&& d& & & d d ddde''''''''''''";function stripRepeat($str) {& $str = preg_replace("/(\s){2,}/",'$1',$str);& $str = preg_replace('{( ?.)\1{4,}}','$1$1$1',$str);& return $str;}?&To prevent any repetitions of characters, you only need this:&?php$str = preg_replace('{(.)\1+}','$1',$str);?&
This function will strip all the HTML-like content in a string.I know you can find a lot of similar content on the web, but this one is simple, fast and robust. Don't simply use the built-in functions like strip_tags(), they dont work so good.Careful however, this is not a correct val you should use additional functions like mysql_real_escape_string and filter_var, as well as custom tests before putting a submission into your database.&?php $html = &&&END&div id="function.preg-split" class="refentry"& Bonjour1 \t&div class="refnamediv"& Bonjour2 \t&h1 class="refname"&Bonjour3 \t&/h1&&h1 class="""&Bonjour4 \t&/h1&&h1 class="*%1"&Bonjour5 \t&/h1&&body&Bonjour6 \t&//body&&&/ body&Bonjour7 \t&////& & & & body&&&a href="image.php" alt="trans" /& & & & &some leftover text...& && & DIV class=noCompliant style = "text-align:" &... and some other ...& dIv & & empty&& &/ empty&& &p& This is yet another text &br& && && that wasn't &b&compliant&/b& too... &br&& /&& && &/p& &div class="noClass" & this one is better but we don't care anyway &/div &&P&& & &input&& type= "text"& name ='my "name' value& = "nothin really." readonly&end of paragraph &/p& &/Div&&& &/div&&& some trailing text END;$html_reg = '/&+\s*\/*\s*([A-Z][A-Z0-9]*)\b[^&]*\/*\s*&+/i';echo htmlentities( preg_replace( $html_reg, '', $html ) );echo htmlentities(strip_tags($html));?&
To split Pascal/CamelCase into Title Case (for example, converting descriptive class names for use in human-readable frontends), you can use the below function:&?phpfunction expandCamelCase($source) {& return preg_replace('/(?&!^)([A-Z][a-z]|(?&=[a-z])[^a-z]|(?&=[A-Z])[0-9_])/', ' $1', $source);}?&Before:& ExpandCamelCaseAPIDescriptorPHP5_3_4Version3_21BetaAfter:& Expand Camel Case API Descriptor PHP 5_3_4 Version 3_21 Beta
It is useful to note that the 'limit' parameter, when used with 'pattern' and 'replace' which are arrays, applies to each individual pattern in the patterns array, and not the entire array.&?php$pattern = array('/one/', '/two/');$replace = array('uno', 'dos');$subject = "test one, one two, one two three";echo preg_replace($pattern, $replace, $subject, 1);?&If limit were applied to the whole array (which it isn't), it would return:test uno, one two, one two threeHowever, in reality this will actually return:test uno, one dos, one two three
People using functions like scandir with user input and protecting against "../" by using preg_replace make sure you run ir recursivly untill preg_match no-long finds it, because if you don't the following can happen.If a user gives the path:"./....//....//....//....//....//....//....//"then your script detects every "../" and removes them leaving:"./../../../../../../../"Which is proberly going back enough times to show root.I just found this vunrability in an old script of mine, which was written several years ago.Always do:&?phpwhile( preg_match( [expression], $input ) ){&& $input = preg_replace( [expression], "", $input );}?&
If you would like to remove a tag along with the text inside it then use the following code.
&?php
preg_replace('/(&tag&.+?)+(&\/tag&)/i', '', $string);
?&
example
&?php $string='&span class="normalprice"&55 PKR&/span&'; ?&
&?php
$string = preg_replace('/(&span class="normalprice"&.+?)+(&\/span&)/i', '', $string);
?&
This will results a null or empty string.
&?php
$string='My String &span class="normalprice"&55 PKR&/span&';
$string = preg_replace('/(&span class="normalprice"&.+?)+(&\/span&)/i', '', $string);
?&
This will results a " My String"
There seems to be some confusion over how greediness works.& For those familiar with Regular Expressions in other languages, particularly Perl: it works like you would expect, and as documented.& Greedy by default, un-greedy if you follow a quantifier with a question mark.There is a PHP/PCRE-specific U pattern modifier that flips the greediness, so that quantifiers are by default un-greedy, and become greedy if you follow the quantifier with a question mark: To make things clear, a series of examples:&?php$preview = "a bunch of stuff &code&this that&/code& and more stuff &code&with a second code block&/code& then extra at the end"; $preview_default = preg_replace('/&code&(.*)&\/code&/is', "&code class=\"prettyprint\"&$1&/code&", $preview);$preview_manually_ungreedy = preg_replace('/&code&(.*?)&\/code&/is', "&code class=\"prettyprint\"&$1&/code&", $preview);$preview_U_default = preg_replace('/&code&(.*)&\/code&/isU', "&code class=\"prettyprint\"&$1&/code&", $preview);$preview_U_manually_greedy = preg_replace('/&code&(.*?)&\/code&/isU', "&code class=\"prettyprint\"&$1&/code&", $preview);echo "Default, no ?: $preview_default\n";echo "Default, with ?: $preview_manually_ungreedy\n";echo "U flag, no ?: $preview_U_default\n";echo "U flag, with ?: $preview_U_manually_greedy\n";?&Results in this:Default, no ?: a bunch of stuff &code class="prettyprint"&this that&/code& and more stuff &code&with a second code block&/code& then extra at the endDefault, with ?: a bunch of stuff &code class="prettyprint"&this that&/code& and more stuff &code class="prettyprint"&with a second code block&/code& then extra at the endU flag, no ?: a bunch of stuff &code class="prettyprint"&this that&/code& and more stuff &code class="prettyprint"&with a second code block&/code& then extra at the endU flag, with ?: a bunch of stuff &code class="prettyprint"&this that&/code& and more stuff &code&with a second code block&/code& then extra at the endAs expected: greedy by default, ? inverts it to ungreedy.& With the U flag, un-greedy by default, ? makes it greedy.
Why not offset parameter to replace the string? It would be helpfulexample:mixed preg_replace (mixed $pattern, mixed $replacement, mixed $subject [, int $limit = -1 [, int & $count [, int $offset = 0]]]) 1 $pattern2 $replacement 3 $subject4 $limit5 $count 6 $offset &- it is planned?
Warning, preg_replace() has an unexpected behaviour on UTF-8 strings when you use an empty regular expression like "/()/" !If you build your regular expression in PHP like this : $words = array();foreach (explode(" ", $what) as $w)& & if (mb_strlen($w) & 0)& & & & $words[] = preg_quote($w, "/");& & return preg_replace('/(' . implode("|",$words) . ')/iu', '&span class="text-maroon"&\\1&/span&', $text);Always check if $words array isn't empty :if (count($words) == 0)& & return $
It may be useful to note that if you pass an associative array as the $replacement parameter, the keys are preserved.&?php$replaced = preg_replace('/foo/', 'bar', ['first' =& 'foobar', 'second' =& 'barfoo']);?&
preg_replace to only show alpha numeric characters$info = "The Development of code . ";$info = preg_replace("/[^a-zA-Z0-9]+/", "", $info);echo $OUTPUTS: TheDevelopmentofcodehttpwwwThis is a good workable code
I have been filtering every userinput with preg_replace since 6 Years now and nothing happened. I am running PHP 5.6.6 and because of historical reasons I still do not use mysqli.Now i noticed that this filter [^0-9a-zA-Z_ -|:\.] won't filter anything from a Sleeping-Hack-String like `%' AnD sLeep(3) ANd '1%`:preg_replace ( '/[^0-9a-zA-Z_ -|:\.]/', '', "%' AnD sLeep(3) ANd '1%" );The reason is, that the fourth Minus has to be escaped!Fix: [^0-9a-zA-Z_ \-|:\.]I tell you because I did not know this and I am pretty sure btw. maybe in older versions of PHP some did not have to escape this minus. Those hacks did not work in the old days, because formerly I have been testing against this.Greetings
Hello there, I would like to share a regex (PHP) sniplet of code I wrote (2012) for myself it is also being used in the Yerico sriptmerge plugin for joomla marked as simple code.. To& compress javascript code and remove all comments from it. It also works with mootools It is fast... (in compairison to other PHP solutions) and does not damage the Javascript it self and it resolves lots of comment removal isseus.//START Remove comments.&& $buffer = str_replace('/// ', '///', $buffer);& & & & && $buffer = str_replace(',//', ', //', $buffer);&& $buffer = str_replace('{//', '{ //', $buffer);&& $buffer = str_replace('}//', '} //', $buffer);&& $buffer = str_replace('*//*', '*/& /*', $buffer);&& $buffer = str_replace('/**/', '/*& */', $buffer);&& $buffer = str_replace('*///', '*/ //', $buffer);&& $buffer = preg_replace("/\/\/.*\n\/\/.*\n/", "", $buffer);&& $buffer = preg_replace("/\s\/\/\".*/", "", $buffer);&& $buffer = preg_replace("/\/\/\n/", "\n", $buffer);&& $buffer = preg_replace("/\/\/\s.*.\n/", "\n& \n", $buffer);&& $buffer = preg_replace('/\/\/w[^w].*/', '', $buffer);&& $buffer = preg_replace('/\/\/s[^s].*/', '', $buffer);&& $buffer = preg_replace('/\/\/\*\*\*.*/', '', $buffer);&& $buffer = preg_replace('/\/\/\*\s\*\s\*.*/', '', $buffer);&& $buffer = preg_replace('/[^\*]\/\/[*].*/', '', $buffer);&& $buffer = preg_replace('/([;])\/\/.*/', '$1', $buffer);&& $buffer = preg_replace('/((\r)|(\n)|(\R)|([^0]1)|([^\"]\s*\-))(\/\/)(.*)/', '$1', $buffer);&& $buffer = preg_replace("/([^\*])[\/]+\/\*.*[^a-zA-Z0-9\s\-=+\|!@#$%^&()`~\[\]{};:\'\",&.&?]/", "$1", $buffer);& $buffer = preg_replace("/\/\*/", "\n/*dddpp", $buffer);& $buffer = preg_replace('/((\{\s*|:\s*)[\"\']\s*)(([^\{\};\"\']*)dddpp)/','$1$4', $buffer);& $buffer = preg_replace("/\*\//", "xxxpp*/\n", $buffer);& $buffer = preg_replace('/((\{\s*|:\s*|\[\s*)[\"\']\s*)(([^\};\"\']*)xxxpp)/','$1$4', $buffer);& $buffer = preg_replace('/([\"\'])\s*\/\*/', '$1/*', $buffer);& $buffer = preg_replace('/(\n)[^\'"]?\/\*dddpp.*?xxxpp\*\//s', '', $buffer);& $buffer = preg_replace('/\n\/\*dddpp([^\s]*)/', '$1', $buffer);& $buffer = preg_replace('/xxxpp\*\/\n([^\s]*)/', '*/$1', $buffer);& $buffer = preg_replace('/xxxpp\*\/\n([\"])/', '$1', $buffer);& $buffer = preg_replace('/(\*)\n*\s*(\/\*)\s*/', '$1$2$3', $buffer);& $buffer = preg_replace('/(\*\/)\s*(\")/', '$1$2', $buffer);& $buffer = preg_replace('/\/\*dddpp(\s*)/', '/*', $buffer);& $buffer = preg_replace('/\n\s*\n/', "\n", $buffer);& $buffer = preg_replace("/([^\'\"]\s*)&!--.*--&(?!(&\/div&)).*/","$1", $buffer);& $buffer = preg_replace('/([^\n\w\-=+\|!@#$%^&*()`~\[\]{};:\'",&.&\/?\\\\])(\/\/)(.*)/', '$1', $buffer);//END Remove comments.& & //START Remove all whitespaces& $buffer = preg_replace('/\s+/', ' ', $buffer);& $buffer = preg_replace('/\s*(?:(?=[=\-\+\|%&\*\)\[\]\{\};:\,\.\&\&\!\@\#\^`~]))/', '', $buffer);& $buffer = preg_replace('/(?:(?&=[=\-\+\|%&\*\)\[\]\{\};:\,\.\&\&\?\!\@\#\^`~]))\s*/', '', $buffer);& $buffer = preg_replace('/([^a-zA-Z0-9\s\-=+\|!@#$%^&*()`~\[\]{};:\'",&.&\/?])\s+([^a-zA-Z0-9\s\-=+\|!@#$%^&*()`~\[\]{};:\'",&.&\/?])/', '$1$2', $buffer);//END Remove all whitespacesI am off coarse not a programmer just wanted to make the plugin work like i wanted it to.... (NOTE: For the webmaster sorry I posted this in the wrong topic before...)
Matching substrings where the match can exist at the end of the string was non-intuitive to me.I found this because:strtotime() interprets 'mon' as 'Monday', but Postgres uses interval types that return short names by default, e.g. interval '1 month' returns as '1 mon'.I used something like this:$str = "mon month monday Mon Monday Month MONTH MON";$strMonth = preg_replace('~(mon)([^\w]|$)~i', '$1th$2', $str);echo "$str\n$strMonth\n";//to output:mon month monday Mon Monday Month MONTH MONmonth month monday Month Monday Month MONTH MONth
[Editor's note: in this case it would be wise to rely on the preg_quote() function instead which was added for this specific purpose]
If your replacement string has a dollar sign or a backslash. it may turn into a backreference accidentally! This will fix it.
I want to replace 'text' with '$12345' but this becomes a backreference to $12 (which doesn't exist) and then it prints the remaining '34'. The function down below will return a string that escapes the backreferences.
OUTPUT:
string(8) "some 345"
string(11) "some \12345"
string(8) "some 345"
string(11) "some $12345"
$a = 'some text';
$b1 = '\12345'; $b2 = '$12345'; $d = array($b1, $b2);
foreach ($d as $b) {
& & $result1 = preg_replace('#(text)#', $b, $a); var_dump($result1);
& & $result2 = preg_replace('#(text)#', preg_escape_back($b), $a); var_dump($result2);
}
function preg_escape_back($string) {
& & $string = preg_replace('#(?&!\\\\)(\\$|\\\\)#', '\\\\$1', $string);
& & return $string;
}
Wrong number of letters in words and how solve this problem and also remove extra spaces in a row:&?php$message_body = 'HHHHHEEEEELLLLLOOOOO& & & & & && IAM COOOOOOOOOOOOOOOOOOOL& & & !!!!!!!!!!';echo "\n".$message_body."\n";$message_body = preg_replace('~(.?)\1{3,}~', '$1', $message_body);$message_body = preg_replace('~\s+~', ' ', trim($message_body));echo "\n".$message_body."\n\n";?&
I wrote some useful function to display date format based on date function particular string. preg_replace function really help me to write this tiny code
&?php
function mysql2formatDate($strn,$outformat='n/j/Y'){
& &
& & return preg_replace("/(\d{4})-(\d{2})-(\d{2})/e","Date('$outformat',strtotime('$0'))",$strn);
}
?&
&?php
& & $c = "2 4 8";
& & echo ($c); $cp = "/(\d)\s(\d)\s(\d)/e"; $cr = "'\\3*\\2+\\1='.(('\\3')*('\\2')+('\\1'))"; $c = preg_replace($cp, $cr, $c);
& & echo ($c); ?&
A simple BB like thing..
&?php
function AddBB($var) {
& & & & $search = array(
& & & & & & & & '/\[b\](.*?)\[\/b\]/is',
& & & & & & & & '/\[i\](.*?)\[\/i\]/is',
& & & & & & & & '/\[u\](.*?)\[\/u\]/is',
& & & & & & & & '/\[img\](.*?)\[\/img\]/is',
& & & & & & & & '/\[url\](.*?)\[\/url\]/is',
& & & & & & & & '/\[url\=(.*?)\](.*?)\[\/url\]/is'
& & & & & & & & );
& & & & $replace = array(
& & & & & & & & '&strong&$1&/strong&',
& & & & & & & & '&em&$1&/em&',
& & & & & & & & '&u&$1&/u&',
& & & & & & & & '&img src="$1" /&',
& & & & & & & & '&a href="$1"&$1&/a&',
& & & & & & & & '&a href="$1"&$2&/a&'
& & & & & & & & );
& & & & $var = preg_replace ($search, $replace, $var);
& & & & return $var;
}
?&
An alternative to the method suggested by sheri is to remember that the regex modifier '$' only looks at the end of the STRING, the example given is a single string consisting of multiple lines.Try:&?php$s = "Testing, testing.\r\n"&& . "Another testing line.\r\n"&& . "Testing almost done.";echo preg_replace('/\.\\r\\n/m', '@\r\n', $s);?&This results in the string:Testing, testing@\r\nAnother testing line@\r\nTesting almost done.
String to filename:&?phpfunction string_to_filename($word) {& & $tmp = preg_replace('/^\W+|\W+$/', '', $word); $tmp = preg_replace('/\s+/', '_', $tmp); return strtolower(preg_replace('/\W-/', '', $tmp)); }?&Returns a usable & readable filename.
&?php$str = "Hi, my name is Arié!&br /&";echo preg_replace('#\bArié\b#u', 'Gontran', $str);echo preg_replace('#\bArié(|\b)#u', 'Gontran', $str);
&?php& & & & & & & & & & $converted& & = array('/(;)/ie', '/(#)/ie', '/(&)/ie', '/(ACTION)/ie', '/(ADD)/ie', '/(ALL)/ie', '/(ALTER)/ie', '/(ANALYZE)/ie', '/(AND)/ie', '/(AS)/ie', '/(ASC)/ie','/(&)/ie', '/(&)/ie', '/(\.)/ie', '/(,)/ie', '/(\?)/ie', '/(`)/ie', '/(!)/ie', '/(@)/ie', '/(\$)/ie', '/(%)/ie', '/(\^)/ie', '/(\*)/ie', '/(\()/ie', '/(\))/ie', '/(_)/ie', '/(-)/ie', '/(\+)/ie', '/(=)/ie', '/(\/)/ie', '/(\|)/ie', '/(\\\)/ie', "/(')/ie", '/(")/ie', '/(:)/');$input_text = preg_replace($converted, "UTF_to_Unicode('\\1')", $text);function UTF_to_Unicode($data){}?&The above example useful for filtering input data, then saving into mysql database, it's not need tobe decoded again, just use UTF-8 as charset.Please Note escaping special chars between delimiter..
For filename tidying I prefer to only ALLOW certain characters rather than converting particular ones that we want to exclude. To this end I use ...&?php& $allowed = "/[^a-z0-9\\040\\.\\-\\_\\\\]/i";& preg_replace($allowed,"",$str));?&Allows letters a-z, digits, space (\\040), hyphen (\\-), underscore (\\_) and backslash (\\\\), everything else is removed from the string.
Be aware that when using the "/u" modifier, if your input text contains any bad UTF-8 code sequences, then preg_replace will return an empty string, regardless of whether there were any matches.This is due to the PCRE library returning an error code if the string contains bad UTF-8.
Hi.
Not sure if this will be a great help to anyone out there, but thought i'd post just in case.
I was having an Issue with a project that relied on $_SERVER['REQUEST_URI']. Obviously this wasn't working on IIS.
(i am using mod_rewrite in apache to call up pages from a database and IIS doesn't set REQUEST_URI). So i knocked up this simple little preg_replace to use the query string set by IIS when redirecting to a PHP error page.
&?php
if(!isset($_SERVER['REQUEST_URI'])){
& $_SERVER['REQUEST_URI'] = preg_replace( '/404;([a-zA-Z]+:\/\/)(.*?)\//i', "/" , $_SERVER['QUERY_STRING'] );
}
?&
Hope this helps someone else out there trying to do the same thing :)
after long time of tring get rid of \n\r and &BR& stuff i've came with this... (i done some changes in clicklein() function...)&?php& & function clickable($url){& & & & $url& & & & & & & & & & & & & & & & & & =& & str_replace("\\r","\r",$url);& & & & $url& & & & & & & & & & & & & & & & & & =& & str_replace("\\n","\n&BR&",$url);& & & & $url& & & & & & & & & & & & & & & & & & =& & str_replace("\\n\\r","\n\r",$url);& & & & $in=array(& & & & '`((?:https?|ftp)://\S+[[:alnum:]]/?)`si',& & & & '`((?&!//)(www\.\S+[[:alnum:]]/?))`si'& & & & );& & & & $out=array(& & & & '&a href="$1"& rel=nofollow&$1&/a& ',& & & & '&a href="" rel=\'nofollow\'&$1&/a&'& & & & );& & & & return preg_replace($in,$out,$url);& & }?&
From what I can see, the problem is, that if you go straight and substitute all 'A's wit 'T's you can't tell for sure which 'T's to substitute with 'A's afterwards. This can be for instance solved by simply replacing all 'A's by another character (for instance '_' or whatever you like), then replacing all 'T's by 'A's, and then replacing all '_'s (or whatever character you chose) by 'A's:
&?php
$dna = "AGTCTGCCCTAG";
echo str_replace(array("A","G","C","T","_","-"), array("_","-","G","A","T","C"), $dna); ?&
Although I don't know how transliteration in perl works (though I remember that is kind of similar to the UNIX command "tr") I would suggest following function for "switching" single chars:
&?php
function switch_chars($subject,$switch_table,$unused_char="_") {
& & foreach ( $switch_table as $_1 =& $_2 ) {
& & & & $subject = str_replace($_1,$unused_char,$subject);
& & & & $subject = str_replace($_2,$_1,$subject);
& & & & $subject = str_replace($unused_char,$_2,$subject);
& & }
& & return $subject;
}
echo switch_chars("AGTCTGCCCTAG", array("A"=&"T","G"=&"C")); ?&
&?PHPfunction strip_tags_attributes($sSource, $aAllowedTags = FALSE, $aDisabledAttributes = FALSE, $aAllowedProperties = 'font|font-size|font-weight|color' . '|text-align|text-decoration|margin|margin-left' . '|margin-top|margin-bottom|margin-right|padding' . '|padding-top|padding-left|padding-right|padding-bottom' . '|width|height'){&& if( !is_array( $aDisabledAttributes ) ){& & & $aDisabledAttributes = array('onabort', 'onactivate', 'onafterprint', 'onafterupdate', 'onbeforeactivate', 'onbeforecopy', 'onbeforecut', 'onbeforedeactivate', 'onbeforeeditfocus', 'onbeforepaste', 'onbeforeprint', 'onbeforeunload', 'onbeforeupdate', 'onblur', 'onbounce', 'oncellchange', 'onchange', 'onclick', 'oncontextmenu', 'oncontrolselect', 'oncopy', 'oncut', 'ondataavaible', 'ondatasetchanged', 'ondatasetcomplete', 'ondblclick', 'ondeactivate', 'ondrag', 'ondragdrop', 'ondragend', 'ondragenter', 'ondragleave', 'ondragover', 'ondragstart', 'ondrop', 'onerror', 'onerrorupdate', 'onfilterupdate', 'onfinish', 'onfocus', 'onfocusin', 'onfocusout', 'onhelp', 'onkeydown', 'onkeypress', 'onkeyup', 'onlayoutcomplete', 'onload', 'onlosecapture', 'onmousedown', 'onmouseenter', 'onmouseleave', 'onmousemove', 'onmoveout', 'onmouseover', 'onmouseup', 'onmousewheel', 'onmove', 'onmoveend', 'onmovestart', 'onpaste', 'onpropertychange', 'onreadystatechange', 'onreset', 'onresize', 'onresizeend', 'onresizestart', 'onrowexit', 'onrowsdelete', 'onrowsinserted', 'onscroll', 'onselect', 'onselectionchange', 'onselectstart', 'onstart', 'onstop', 'onsubmit', 'onunload');&& }&& && $sSource = stripcslashes( $sSource );& & & & & & && $sSource = strip_tags( $sSource, $aAllowedTags );& & & & && if( empty($aDisabledAttributes) ){& & & return $sSource;&& }&& $aDisabledAttributes = @ implode('|', $aDisabledAttributes);& & & & && $sSource = preg_replace('/&(.*?)&/ie', "'&' . preg_replace(array('/javascript:[^\"\']*/i', '/(" . $aDisabledAttributes . ")[ \\t\\n]*=[ \\t\\n]*[\"\'][^\"\']*[\"\']/i', '/\s+/'), array('', '', ' '), stripslashes('\\1')) . '&'", $sSource );&& $sSource = preg_replace('/\s(' . $aDisabledAttributes . ').*?([\s\&])/', '\\2', $sSource);& & & & & & && $regexp = '@([^;"]+)?(?&!'. $aAllowedProperties .'):(?!\/\/(.+?)\/)((.*?)[^;"]+)(;)?@is';& & && $sSource = preg_replace($regexp, '', $sSource);&& $sSource = preg_replace('@[a-z]*=""@is', '', $sSource); & & & & & & && return $sSource;}?&Online resource help skype name : globya good luck !
This function takes a URL and returns a plain-text version of the page. It uses cURL to retrieve the page and a combination of regular expressions to strip all unwanted whitespace. This function will even strip the text from STYLE and SCRIPT tags, which are ignored by PHP functions such as strip_tags (they strip only the tags, leaving the text in the middle intact).
Regular expressions were split in 2 stages, to avoid deleting single carriage returns (also matched by \s) but still delete all blank lines and multiple linefeeds or spaces, trimming operations took place in 2 stages.
&?php
function webpage2txt($url)
{
$user_agent = “Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)”;
$ch = curl_init();& & curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_FAILONERROR, 1);& & & & & & & curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);& & curl_setopt($ch, CURLOPT_RETURNTRANSFER,1); curl_setopt($ch, CURLOPT_PORT, 80);& & & & & & curl_setopt($ch, CURLOPT_TIMEOUT, 15); curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);
$document = curl_exec($ch);
$search = array(’@&script[^&]*?&.*?&/script&@si’,& // Strip out javascript
‘@&style[^&]*?&.*?&/style&@siU’,& & // Strip style tags properly
‘@&[\/\!]*?[^&&]*?&@si’,& & & & & & // Strip out HTML tags
‘@&![\s\S]*?–[ \t\n\r]*&@’,& & & && // Strip multi-line comments including CDATA
‘/\s{2,}/’,
$text = preg_replace($search, “\n”, html_entity_decode($document));
$pat[0] = “/^\s+/”;
$pat[2] = “/\s+\$/”;
$rep[0] = “”;
$rep[2] = ” “;
$text = preg_replace($pat, $rep, trim($text));
return $
}
?&
Potential uses of this function are extracting keywords from a webpage, counting words and things like that. If you find it useful, drop us a comment and let us know where you used it.
Wasted several hours because of this:
&?php
$str='It's a string with HTML entities';
preg_replace('~&#(\d+);~e', 'code2utf($1)', $str);
?&
This code must convert numeric html entities to utf8. And it does with a little exception. It treats wrong codes starting with &#0
The reason is that code2utf will be called with leading zero, exactly what the pattern matches - code2utf(039).
And it does matter! PHP treats 039 as octal number.
Try &?php print(011); ?&
Solution:
&?php preg_replace('~&#0*(\d+);~e', 'code2utf($1)', $str); ?&
Also worth noting is that you can use array_keys()/array_values() with preg_replace like:
&?php
$subs = array(
& '/\[b\](.+)\[\/b\]/Ui' =& '&strong&$1&/strong&',
& '/_(.+)_/Ui' =& '&em&$1&/em&'
& ...
& ...
);
$raw_text = '[b]this is bold[/b] and this is _italic!_';
$bb_text = preg_replace(array_keys($subs), array_values($subs), $raw_text);
?&
Note that it is in most cases much more efficient to use preg_replace_callback(), with a named function or an anonymous function created with create_function(), instead of the /e modifier.& When preg_replace() is called with the /e modifier, the interpreter must parse the replacement string into PHP code once for every replacement made, while preg_replace_callback() uses a function that only needs to be parsed once.
I got problem echoing text that contains double-quotes into a text field. As it confuses value option. I use this function below to match and replace each pair of them by smart quotes. The last one will be replaced by a hyphen(-).
It works for me.
&?php
function smart_quotes($text) {
& $pattern = '/"((.)*?)"/i';
& $text = preg_replace($pattern,"“\\1”",stripslashes($text));
& $text = str_replace("\"","-",$text);
& $text = addslashes($text);
& return $text;
}
?&
Based on previous comment, i suggest
( this function already exist in php 6 )
&?php
function unicode_decode($str){
& & return preg_replace(
& & & & '#\\\u([0-9a-f]{4})#e',
& & & & "unicode_value('\\1')",
& & & & $str);
}
function unicode_value($code) {
& & $value=hexdec($code);
& & if($value&0x0080)
& & & & return chr($value);
& & elseif($value&0x0800)
& & & & return chr((($value&0x07c0)&&6)|0xc0)
& & & & & & .chr(($value&0x3f)|0x80);
& & else
& & & & return chr((($value&0xf000)&&12)|0xe0)
& & & & .chr((($value&0x0fc0)&&6)|0x80)
& & & & .chr(($value&0x3f)|0x80);
}
?&
[EDIT BY danbrown AT php DOT net:& This function originally written by mrozenoer AT overstream DOT net.]
I got sick of trying to replace just a word, so I decided I would write my own string replacement code. When that code because far to big and a little faulty I decided to use a simple preg_replace:
&?php
function word_replace($search, $replace, $subject) {
& & return preg_replace('/[a-zA-Z]+/e', '\'\0\' == \'' . $search . '\' ? \'' . $replace . '\': \'\0\';', $subject);
}
?&
I hope that this code helpes someone!
People using the /e modifier with preg_replace should be aware of the following weird behaviour. It is not a bug per se, but can cause bugs if you don't know it's there.The example in the docs for /e suffers from this mistake in fact.With /e, the replacement string is a PHP expression. So when you use a backreference in the replacement expression, you need to put the backreference inside quotes, or otherwise it would be interpreted as PHP code. Like the example from the manual for preg_replace:preg_replace("/(&\/?)(\w+)([^&]*&)/e",& & & & & && "'\\1'.strtoupper('\\2').'\\3'",& & & & & && $html_body);To make this easier, the data in a backreference with /e is run through addslashes() before being inserted in your replacement expression. So if you have the string He said: "You're here"It would become: He said: \"You\'re here\"...and be inserted into the expression.However, if you put this inside a set of single quotes, PHP will not strip away all the slashes correctly! Try this: print ' He said: \"You\'re here\" '; Output: He said: \"You're here\"This is because the sequence \" inside single quotes is not recognized as anything special, and it is output literally.Using double-quotes to surround the string/backreference will not help either, because inside double-quotes, the sequence \' is not recognized and also output literally. And in fact, if you have any dollar signs in your data, they would be interpreted as PHP variables. So double-quotes are not an option.The 'solution' is to manually fix it in your expression. It is easiest to use a separate processing function, and do the replacing there (i.e. use "my_processing_function('\\1')" or something similar as replacement expression, and do the fixing in that function).If you surrounded your backreference by single-quotes, the double-quotes are corrupt:$text = str_replace('\"', '"', $text);People using preg_replace with /e should at least be aware of this.I'm not sure how it would be best fixed in preg_replace. Because double-quotes are a really bad idea anyway (due to the variable expansion), I would suggest that preg_replace's auto-escaping is modified to suit the placement of backreferences inside single-quotes (which seemed to be the intention from the start, but was incorrectly applied).
if your intention to code and decode mod_rewrite urls and handle it with php and mysql ,this should workto convert to url$url = preg_replace('/[^A-Za-z0-9_-]+/', '-', $string);And to check in mysql with the url value,use the same expression discounting '-'.first replace the url value& with php using preg_replace& and use with mysql REGEXP$sql = "select * from table where fieldname_to_check REGEXP '".preg_replace("/-+/",'[^A-Za-z0-9_]+',$url)."'"
If you want to add simple rich text functionality to HTML input fields, preg_replace can be quite handy.For example, if you want users to be able to bold text by typing *text* or italicize it by typing _text_, you can use the following function.&?phpfunction encode(&$text) {& & $text = preg_replace('/\*([^\*]+)\*/', '&b&\1&/b&', $text);& & $text = preg_replace('/_([^_]+)_/', '&i&\1&/i&', $text);& & return $text;& & }?&This works for nested tags, too, although it will not fix nesting mistakes.To make this function more efficient, you could put the delimiters (* and _, in this case) and their HTML tag equivalents in an array and loop through them.
I find it useful to output HTML form names to the user from time to time while going through the $_GET or $_POST on a user's submission and output keys of the GET or POST array... the only problem being in the name attribute I follow common programming guidelines and have names like the following: eventDate, eventTime, userEmail, etc. Not great to just output to the user-- so I came up with this function. It just adds a space before any uppercase letter in the string.
&?php
function caseSwitchToSpaces( $stringVariableName )
{
$pattern = '/([A-Z])/';
$replacement = ' ${1}';
return preg_replace( $pattern, $replacement, $stringVariableName );
}
echo( caseSwitchToSpaces( "helloWorld" ) );
?&
would output:
"hello World"
You could also do title-style casing to it if desired so the first word isn't lowercase.
Warning: not all strings are from a regular language, some are from context free grammars.Here is a pair of strings that are impossible to correctly parse with regular expressions:a*(b+(c*d)-e)/(f-(g*h)+i)-ja[i]b[i]c[/i]d[/i]e[i]f[i]g[/i]h[/i]
Replacement of line numbers, with replacement limit per line.Solution that worked for me.I have a file with tasks listed each starting from number, and only starting number should be removed because forth going text has piles of numbers to be omitted.56 Patient A of 46 years suffering ... ...57 Newborn of 26 weeks was ...58 Jane, having age 18 years recollects onsets of ......587 Patient of 70 years ...etc.&?php$array = file($file, true);foreach($array as $value){& & if(preg_match('%^[0-9]{3}%', $value)) & & {& & & & $value = preg_replace('%^[0-9]{3}%', '-HERE WAS XXX NUMBER-', $value, 1);& & }& & & & & & & & & & elseif(preg_match('%^[0-9]{2}%', $value)) {& & & & $value = preg_replace('%^[0-9]{2}%', '-HERE WAS XX NUMBER-', $value, 1);& & }& & & & & & & & & & elseif(preg_match('%^[0-9]%', $value)) {& & & & $value = preg_replace('%^[0-9]%', '-HERE WAS X NUMBER-', $value, 1);& & }& & & & & & & & & & $arr[] = array($value);& & & & }}?&
Take care when you try to strip whitespaces out of an UTF-8 text. Using something like:&?php$text = preg_replace( "{\s+}", ' ', $text );?&brokes in my case the letter à which is hex c3a0. But a0 is a whitespace. So use &?php$text = preg_replace( "{[ \t]+}", ' ', $text );?&to strip all spaces and tabs, or better, use a multibyte function like mb_ereg_replace.
Hi,as I wasn't able to find another way to do this, I wrote a function converting any UTF-8 string into a correct NTFS filename (see ).&?phpfunction strToNTFSFilename($string){& $reserved = preg_quote('\/:*?"&&', '/');& return preg_replace("/([\\x00-\\x1f{$forbidden}])/e", "_", $string);}?&It converts all control characters and filename characters which are reserved by Windows ('\/:*?"&&') into an underscore.This way you can safely create an NTFS filename out of any UTF-8 string.
If you want to limit multiple occurences of any char in a sequence you might want to use this function.&?phpfunction limit_char_repeat($string,$maxrepeat){& & return preg_replace("/(.)\\1{".$maxrepeat.",}/ms",str_repeat('\1',$maxrepeat),$string);}?&Example:&?php$string="---------------------Heeeeeeeeeeeeeeeeeeeello Woooooooooooooooorld!!!!!!!!!!!!!!!!!!!!!!!!===============================================================================================================~~~~~~~~~~~~~~~~ ~ ~ ~";echo limit_char_repeat($string,5);?&Output:-----Heeeeello Wooooorld!!!!!=====~~~~~ ~ ~ ~
if you want to replace only the content of specific div using the ID you can do this :&?php$id = "my-id";$content = '&div id="my-id"&Hello World&/div&&div& id="other-id"& My World&/div&';$replacement = "Hello Planet";$result& =& preg_replace('/(&div.*?id=\"'.$id.'\"[^&]*&)(.*?)(&\/div&)/i', "$1{$replacement}$3", $content);&& echo $result:?&should print : &div id="my-id"&Hello Planet&/div&&div& id="other-id"& My World&/div&
It is recommended that str_replace should be used instead of preg_replace when regex is not needed. In particular, at
it says "If you don't need fancy replacing rules (like regular expressions), you should always use this function instead of preg_replace()."While this is usually true, I have found a significant exception to this guideline and benchmarked to show that str_replace is in fact slower in the case when the pattern to be replaced is an array. In particular, when the number of elements in the pattern gets to be around 7, then the preg_replace is faster. Of course this would depend on the specifics of the regex.In my case I had pattern arrays with about 40 elements. This becomes far slower with str_replace when there is a simple regex that will do the job.Below is the benchmark with some examples of arrays for patterns and an equivalent regex.&?php$iterations = 1000000;$str1 = 'this is a - test';$begin = microtime(true);for ($i = 0; $i & $iterations; $i++){}$end = microtime(true);$empty_loop_time = $end - $begin;echo "empty loop takes $empty_loop_time microseconds.\n";'#','^','*','_','=','+','\\','?','|','&','&','{','}','’','`','~','“','?','$');$aStr = array('0','1','2','3','4','5','6');$cnt = count($aStr);echo 'Array size: ' . $cnt . "\n";$begin = microtime(true);for ($i = 0; $i & $iterations; $i++){& & $str2 = str_replace($aStr,'',$str1);}$end = microtime(true);$test1_loop_time = $end - $begin;echo ' *** str_replace:& ';$test_time = ($test1_loop_time - $empty_loop_time) * 1000000 / $iterations;echo "$test_time microseconds.\n";$begin = microtime(true);for ($i = 0; $i & $iterations; $i++){& & $str2 = preg_replace('/[^a-zA-Z\s]/','',$str1);}$end = microtime(true);$test2_loop_time = $end - $begin;echo ' *** preg_replace: ';$test_time = ($test2_loop_time - $empty_loop_time) * 1000000 / $iterations;echo "$test_time microseconds.\n";?&
simple function to remove comments from string&?phpfunction remove_comments( & $string ){& $string = preg_replace("%(#|;|(//)).*%","",$string);& $string = preg_replace("%/\*(?:(?!\*/).)*\*/%s","",$string); return $string;}?&USAGE:&?php$config = file_get_contents("config.cfg");print "before:".$config;remove_comments($config);print "after:".$config;?&OUTPUT:before:/* *& this is config file */; logdirLOGDIR ./log/// logfileLOGFILE main.log# loglevelLOGLEVEL 3after:LOGDIR ./log/LOGFILE main.logLOGLEVEL 3
I have written a short introduction and a colorful cheat sheet for Perl Compatible Regular Expressions (PCRE):
Reading arguments against variables in CSS got me to thinking. Process your CSS files in a fashion similar to the following. This particular routine is certainly not the most efficient way, but is what I came up with on the spur of the moment. The prefix token is entirely arbitrary - everything between the leading colon and terminating semicolon is the target. In this way, default values can be put in place, and the constant identifiers simply left as comments, should the stylesheet be use this would also inhibit your editor from emitting errors about your odd syntax. The declaration pattern at the top assumes something like this:/*@css_const [& && bgc_a=#ccccee,& & & & fc_a=#000099,& && bgc_b=#5555cc,& && bgc_c=#eeeeff,& && bgc_d=#599fee ]*/...within the target CSS file.Usage like so:.Element {& && font-size:10& && color:#000/*fc_a*/;& && background-color:#fff/*bgc_a*/;}And then...&?php$dec_pat = '/^\/\*\@css_const\s+\[(.*)\]\s+\*\//Ums';preg_match_all($dec_pat,$css,$m);$lhs = array();$rhs = array();foreach($m[1] as &$p) {& & $p = explode(",",$p);& & foreach($p as &$q) {& & & & list($k,$v) = explode("=",trim($q));& & & & $lhs[] = '/(\w+\:).*\/\*' . $k . '\*\/;$/Um';& & & & $rhs[] = '\1' . $v . ';';& & }}$css = preg_replace($lhs,$rhs,$css);?&...resulting, of course, in:.Element {& && font-size:10& && color:#000099;& && background-color:#}Again, efficiency was not the immediate goal, so please don't slay me...
yes you can use different pattern delimiters useful when working on an Url
&?php
$logo=preg_replace('#\\.\\./images#','/images',$logo);
?&
"preg_replace" is able to be exploited with a DOS attack by the user submitting a very long string.& One way I combat this is by using "substr" first to grab the first part of the string.$input_string = $_GET['user_input'];// If necessary you can log any user attempts to submit a long string$string_length = strlen($input_string);if($string_lenght & 100){log_func($_SERVER['REMOTE_ADDR'], $string_length, $input_string);}$input_string_cut = substr($input_string,0,100);$string = preg_replace('/[^a-zA-Z0-9]/', '', $input_string_cut);echo($string);
It may seem useless, but the font tag in Internet Explorer won't recognize compressed hexa values. This is a simple function to uncompress hexa values in the font tag&?phpfunction colorfix($text) {& & return preg_replace('/"#([a-f0-9])([a-f0-9])([a-f0-9])"/i', '"#$1$1$2$2$3$3"', $text);}?&
The instructions say, use \\\\ (four backslashes) to represent a backslash.& You can shorthand this and use \\\ (three backslashes) to represent a backslash, because of the way the parsers read it.It appears the double escaping is required because the string is parsed twice, once by PHP and once by the regular expression generator. Thus it is expected that the PHP parser turns both instances above into \\ (two backslashes) for the PCRE parser.}