Php preg_replace function basics and instance code

// Preg_replace (mixed $ pattern, mixed $ replacement, mixed $ subject [, int $ limit =-1 [, int & $ count]) subject: match search mode, replace
/*
The pattern to be searched. It can be a string or a string array.

After the electronic modifier causes the preg_replace function () to replace the treatment, the appropriate reference as a parameter is replaced by the php Tutorial code. Tip: Make sure that the replacement constitutes a valid php code string. Otherwise, php will complain about parsing errors including the preg_replace function line.

Return value

The preg_replace function () returns an array. If the parameter in this issue is an array or a string, otherwise.

If a match is found, a new problem will occur. Otherwise, the returned topic will remain unchanged or null if an error occurs.
*/

// Instance 1

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$ String = '0000l 15,200 3 '; $ Pattern = '/(w +) (d +), (d +)/I '; $ Replacement = '$ {1} 1, $3 '; Echo preg_replace ($ pattern, $ replacement, $ string );

// Instance 2

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$ String = 'The quick brown fox jumped over the lazy dog .'; $ Patterns = array (); $ Patterns [0] = '/quick /'; $ Patterns [1] = '/brown /'; $ Patterns [2] = '/fox /'; $ Replacements = array (); $ Replacements [2] = 'bear '; $ Replacements [1] = 'black '; $ Replacements [0] = 'slow '; Echo preg_replace ($ patterns, $ replacements, $ string );

// We should get what we want through the ksorting mode and substitution.

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Ksort ($ patterns ); Ksort ($ replacements ); Echo preg_replace ($ patterns, $ replacements, $ string );

// Replace several values

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$ Patterns = array ('/(19 | 20) (d {2})-(d {1, 2})-(d {1, 2 })/', '/^ S * {(w +)} s * = /'); $ Replace = array ('//', '$ = '); Echo preg_replace ($ patterns, $ replace, '{startdate} = ');

// Filter all html tags

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Preg_replace ("/(</?) (W +) ([^>] *>)/e ", "'\ 1'. strtoupper (' \ 2'). '\ 3 '", $ Html_body );

// Filter all script code

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$ User_agent = "mozilla/4.0 (compatible; msie 5.01; windows nt 5.0 )"; $ Ch = curl_init (); // initialize curl handle Curl_setopt ($ ch, curlopt_url, $ url); // set url to post Curl_setopt ($ ch, curlopt_failonerror, 1); // fail on errors Curl_setopt ($ ch, curlopt_followlocation, 1); // allow redirects Curl_setopt ($ ch, curlopt_returntransfer, 1); // return into a variable Curl_setopt ($ ch, curlopt_port, 80); // set the port number Curl_setopt ($ ch, curlopt_timeout, 15); // times out after 15 s Curl_setopt ($ ch, curlopt_useragent, $ user_agent ); $ Document = curl_exec ($ ch ); $ Search = array ('@ <script [^>] *?>. *? </Script> @ Si', // strip out javascript tutorial www.111cn.net '@ <Style [^>] *?>. *? </Style> @ siu ', // strip style tags properly '@ <[/!] *? [^ <>] *?> @ Si', // strip out html tags '@ <! [Ss] *? -[] *> @ ', // Strip multi-line comments including cdata '/S {2 ,}/', ); $ Text = preg_replace ($ search, "", html_entity_decode ($ document )); $ Pat [0] = "/^ s + /"; $ Pat [2] = "/s + $ /"; $ Rep [0] = ""; $ Rep [2] = ""; $ Text = preg_replace ($ pat, $ rep, trim ($ text )); Return $ text; }

/*
This function accepts a url and returns the plain text version of the page. It uses curl to retrieve web pages, a combination of regular expressions, to remove all unnecessary spaces. This function even gets rid of form and script markup, which is ignored by php functions, such as using strip_tags (they strip the unique markup text and leave the complete text in the middle ).

A regular expression is divided into two phases to avoid deleting a single (also matching by s) and pressing enter, but still deleting all blank rows and multiple linefeeds or spaces, the repair procedure was performed in two phases.
*/
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