PHP implements that each keyword only needs to be replaced once-PHP Tutorial-php.cn

PHP implements that each keyword only needs to be replaced once

墨辰丷

Release： 2023-03-30 08:44:02

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This article mainly introduces PHP to realize that each keyword only needs to be replaced once. Interested friends can refer to it. I hope it will be helpful to everyone.

(1) Use the preg_replace function to implement this function. Because the preg_replace function itself can control the number of replacements, I thought of it from the beginning. The specific implementation method is as follows:

//可以实现替换次数的控制，不仅限于只替换一次，比如$limit为2的时候表示一个词出现很多吃的时候仅替换2次，-1表示全部替换。$search 和 $replace 都可以是字符串或者数组，但必须对应 
function str_replace_limit($search,$replace,$content,$limit=-1){ 
  if(is_array($search)){ 
    foreach ($search as $k=>$v){ 
      $search[$k]=&#39;`&#39;.preg_quote($search[$k],&#39;`&#39;).&#39;`&#39;; 
    } 
  }else{ 
    $search=&#39;`&#39;.preg_quote($search,&#39;`&#39;).&#39;`&#39;; 
  } 
  //把图片描述去掉 
  $content=preg_replace("/alt=([^ >]+)/is",&#39;&#39;,$content); 
  return preg_replace($search,$replace,$content,$limit); 
}

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(2) Use the substr_replace function to implement, but only one replacement can be achieved here

//首先找到关键字所在位置，然后使用 substr_replace（系统函数）进行替换操作 
function str_replace_once($search,$replace,$content){ 
  //把图片描述去掉 
  $content=preg_replace("/alt=([^ >]+)/is",&#39;&#39;,$content); 
  $pos=strpos($content,$search); 
  if($pos===false){ 
    return $haystack; 
  } 
  return substr_replace($content,$replace,$pos,strlen($search)); 
}

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Summary: The above is the entire content of this article, I hope it can be helpful to everyone learning helps.

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