PHP keyword replacement class avoids repeated replacement, retains and restores the original link

Reprint: http://www.169it.com/blog_article/601549531.html

Main content of this section:
A keyword replacement class

can be mainly used for keyword filtering, or keyword search and replacement.

Implementation process analysis:
Keyword replacement is actually a str_replace() process. If a simple str_replace is faced with 10W keywords, it only takes about 2 seconds to write a 1W word article.
The problem:
The keyword has been replaced more than once. For example, a needs to be replaced with a, but the result may be a, etc. so.

For this reason, a method is needed to protect the replaced tags. Then before processing the article, replace the tags such as [_tnum_] and then restore it after the article is processed.

Another question, what if there is [_tnum_] itself in the keyword or article, then you need to exclude this. str_replace cannot be used here, but preg_replace needs to be used to exclude it with regular expressions.

The third question is, what if there are two keywords a and ab? I hope to match the long ones first and then match the short ones, so I need to sort them before matching.

The last question, when str_replace is changed to preg_replace, it becomes slower. It takes 5 seconds to match 100,000 times for the same paragraph. Among the string processing functions, strpos is faster. Then use strpos to find the keywords first. 100,000 queries take less than 1 second. Even if it is 1 million, it will take more than 8 seconds.

A keyword matching replacement class, code:

Code example:

/*
* Keyword matching class
* @author ylx
* @ packet mipang
* Usage examples
* $str = "Green-shelled egg chicken spreads Van der Sar next year, next year 1 will spread the room Lucas local army";
* $key = new KeyReplace($str,array ("xxxx"=>"sadf","Next year 1"=>'http://baidu.com',"Next year"=>'google.com'));
* echo $ key->getResultText();
* echo $key->getRuntime();
*/
class KeyReplace
{
private $keys = array();
private $text = "";
private $runtime = 0;
private $url = true;
private $stopkeys = array();
private $all = false;
/**
* @access public
* @param string $text specifies the article to be processed
* @param array $keys specifies the dictionary phrase array(key=>url,...) url can be an array, if it is an array it will be replaced randomly One of them
* @param array $stopkeys specifies stop words array(key,...) The words in this will not be processed
* @param boolean $url true means to replace it with a link, otherwise it will only be replaced
* @param boolean $all true means replace all found words, otherwise only replace the first time
*/
public function __construct($text='',$keys=array( ),$url=true,$stopkeys=array(),$all=false) {
$this->keys = $keys;
$this->text = $text;
$this->url = $url;
$this->stopkeys = $stopkeys;
$this->all = $all;
}

/**
* Get the processed article
* @access public
* @return string text
*/
public function getResultText() {
$start = microtime( true);
$keys = $this->hits_keys();

$keys_tmp = array_keys()($keys);

function cmp($a, $b){
if (mb_strlen($a) = = mb_strlen($b)) {
return 0;
}
return (mb_strlen($a) < mb_strlen($b)) ? 1 : -1;
}

usort($keys_tmp,"cmp");

foreach($keys_tmp as $key){

if(is_array($keys[$key])){
$url = $keys[$key][rand(0,count($keys[$key]) -1)];
}else
$url = $keys[$key];

          $this->text = $this->r_s($this->text,$key,$url);

}
  $this->runtime = microtime(true)-$start;

  return $this->text;
  }
  /**
* Get the processing time
* @access public
* @return float
*/
  public function getRuntime() {

  return $ this->runtime;

}

  /**
* Set keywords
* @access public
* @param array $keys array(key=>url,...)
*/
  public function setKeys($keys) {

    $this->keys = $keys;

  }
  /**
* Set stop words
* @access public
* @param array $keys array(key,...)
*/
  public function setStopKeys($keys) {

    $this->stopkeys = $keys;

  }
  /**
* Set article
* @access public
* @param string $text
*/
  public function setText($text) {

    $this->text = $text;

  }

  /**
* Used to find the hit keywords in the string
* @access public
* @return array $keys Returns the matched word array(key=>url,...)
*/
  public function hits_keys(){
    $ar = $this->keys;
    $ar = $ar?$ar:array();
    $result=array();
    $str = $this->text;
    foreach($ar as $k=>$url){
      $k = trim($k);
      if(!$k)
 continue;
      if(strpos($str,$k)!==false && !in_array($k,$this->stopkeys)){
 $result[$k] = $url;
      }
    }
    return $result?$result:array();
  }

  /**
* Used to find the hit stop words in the string
* @access public
* @return array $keys Returns the matched word array(key,...)
*/
  public function hits_stop_keys(){
    $ar = $this->stopkeys;
    $ar = $ar?$ar:array();
    $result=array();
    $str = $this->text;
    foreach($ar as $k){
      $k = trim($k);
      if(!$k)
 continue;
      if(strpos($str,$k)!==false && in_array($k,$this->stopkeys)){
 $result[] = $k;
      }
    }
    return $result?$result:array();
  }

  /**
* Handle the replacement process
* @access private
* @param string $text Replaced person
* @param string $key Keyword
* @param string $url Link
* @return string $text Processed article
*/
  private function r_s($text,$key,$url){

    $tmp = $text;

    $stop_keys = $this->hits_stop_keys();

    $stopkeys = $tags = $a = array();
    if(preg_match_all("#]+>[^<]*]*>#su",$tmp,$m)){
      $a=$m[0];

      foreach($m[0] as $k=>$z){
 $z = preg_replace("###s","#",$z);

 $tmp = preg_replace('#'.$z.'#s',"[_a".$k."_]",$tmp,1);
      }

    };

    if(preg_match_all("#<[^>]+>#s",$tmp,$m)){
      $tags = $m[0];
      foreach($m[0] as $k=>$z){
 $z = preg_replace("###s","#",$z);
 $tmp = preg_replace('#'.$z.'#s',"[_tag".$k."_]",$tmp,1);
      }
    }
    if(!empty($stop_keys)){
      if(preg_match_all("#".implode("|",$stop_keys)."#s",$tmp,$m)){
 $stopkeys = $m[0];
 foreach($m[0] as $k=>$z){
   $z = preg_replace("###s","#",$z);
   $tmp = preg_replace('#'.$z.'#s',"[_s".$k."_]",$tmp,1);
 }
      }
    }
    $key1 = preg_replace("#([#()[]*])#s","\\$1",$key);

    if($this->url)
      $tmp = preg_replace("#(?![_s|[_a|[_|[_t|[_ta|[_tag)".$key1."(?!agd+_]|gd+_]|d+_]|sd+_]|_])#us",''.$key.'',$tmp,$this->all?-1:1);
    else
      $tmp = preg_replace("#(?![_s|[_a|[_|[_t|[_ta|[_tag)".$key1."(?!agd+_]|gd+_]|d+_]|sd+_]|_])#us",$url,$tmp,$this->all?-1:1);

    if(!empty($a)){

      foreach($a as $n=>$at){

 $tmp = str_replace("[_a".$n."_]",$at,$tmp);

      }    

    }    
    if(!empty($tags)){

      foreach($tags as $n=>$at){

 $tmp = str_replace("[_tag".$n."_]",$at,$tmp);

      }    

    }    
    if(!empty($stopkeys)){

      foreach($stopkeys as $n=>$at){

 $tmp = str_replace("[_s".$n."_]",$at,$tmp);

      }    

    }    
    return $tmp;
  }
}

以上就介绍了php关键词替换的类避免重复替换，保留与还原原始链接，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。