本文实例讲述了PHP函数实现从一个文本字符串中提取关键字的方法。分享给大家供大家参考。具体分析如下：
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。功能正常工作，但我正在改进，因此，感兴趣的朋友可以提出改进意见。
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 /** * Finds all of the keywords (words that appear most) on param $str * and return them in order of most occurrences to less occurrences. * @param string $str The string to search for the keywords. * @param int $minWordLen[optional] The minimun length (number of chars) of a word to be considered a keyword. * @param int $minWordOccurrences[optional] The minimun number of times a word has to appear * on param $str to be considered a keyword. * @param boolean $asArray[optional] Specifies if the function returns a string with the * keywords separated by a comma ($asArray = false) or a keywords array ($asArray = true). * @return mixed A string with keywords separated with commas if param $asArray is true, * an array with the keywords otherwise. */ function extract_keywords($str, $minWordLen = 3, $minWordOccurrences = 2, $asArray = false) { function keyword_count_sort($first, $sec) { return $sec[1] - $first[1]; } $str = preg_replace('/[^w0-9 ]/', ' ', $str); $str = trim(preg_replace('/s+/', ' ', $str)); $words = explode(' ', $str); $keywords = array(); while(($c_word = array_shift($words)) !== null) { if(strlen($c_word) <= $minWordLen) continue; $c_word = strtolower($c_word); if(array_key_exists($c_word, $keywords)) $keywords[$c_word][1]++; else $keywords[$c_word] = array($c_word, 1); } usort($keywords, 'keyword_count_sort'); $final_keywords = array(); foreach($keywords as $keyword_det) { if($keyword_det[1] < $minWordOccurrences) break; array_push($final_keywords, $keyword_det[0]); } return $asArray ? $final_keywords : implode(', ', $final_keywords); } //How to use //Basic lorem ipsum tex新闻热点
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