PHP从一个文本字符串中提取关键字的函数
这是一个函数定位接收一个字符串作为参数（连同其他配置可选参数），并且定位该字符串中的所有关键字（出现最多的词），返回一个数组或一个字符串由逗号分隔的关键字。
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/** |
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* Finds all of the keywords (words that appear most) on param $str |
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* and return them in order of most occurrences to less occurrences. |
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* @param string $str The string to search for the keywords. |
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* @param int $minWordLen[optional] The minimun length (number of chars) of a word to be considered a keyword. http://www.zzzyk.com/ |
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* @param int $minWordOccurrences[optional] The minimun number of times a word has to appear |
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* on param $str to be considered a keyword. |
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* @param boolean $asArray[optional] Specifies if the function returns a string with the |
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* keywords separated by a comma ($asArray = false) or a keywords array ($asArray = true). |
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* @return mixed A string with keywords separated with commas if param $asArray is true, |
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* an array with the keywords otherwise. |
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*/ |
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function extract_keywords($str, $minWordLen = 3, $minWordOccurrences = 2, $asArray = false) |
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{ |
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function keyword_count_sort($first, $sec) |
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{ |
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return $sec[1] - $first[1]; |
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} |
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$str = preg_replace('/[^\\w0-9 ]/', ' ', $str); |
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$str = trim(preg_replace('/\s+/', ' ', $str)); |
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|
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$words = explode(' ', $str); |
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$keywords = array(); |
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while(($c_word = array_shift($words)) !== null) |
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{ |
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if(strlen($c_word) <= $minWordLen) continue; |
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|
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$c_word = strtolower($c_word); |
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if(array_key_exists($c_word, $keywords)) $keywords[$c_word][1]++; |
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else $keywords[$c_word] = array($c_word, 1); |
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} |
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usort($keywords, 'keyword_count_sort'); |
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|
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$final_keywords = array(); |
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foreach($keywords as $keyword_det) |
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{ |
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if($keyword_det[1] < $minWordOccurrences) break; |
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array_push($final_keywords, $keyword_det[0]); |
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} |
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return $asArray ? $final_keywords : implode(', ', $final_keywords); |
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} |
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|
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//How to use |
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|
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//Basic lorem ipsum text to extract the keywords |
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$text = " |
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Lorem ipsum dolor sit amet, consectetur adipiscing elit. |
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Curabitur eget ipsum ut lorem laoreet porta a non libero. |
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Vivamus in tortor metus. Suspendisse potenti. Curabitur |
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metus nisi, adipiscing eget placerat suscipit, suscipit |
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vitae felis. Integer eu odio enim, sed dignissim lorem. |
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In fringilla molestie justo, vitae varius risus lacinia ac. |
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Nulla porttitor justo a lectus iaculis ut vestibulum magna |
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egestas. Ut sed purus et nibh cursus fringilla at id purus. |
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"; |
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//Echoes: lorem, suscipit, metus, fringilla, purus, justo, eget, vitae, ipsum, curabitur, adipiscing |
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echo extract_keywords($text); |
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