In-depth discussion of the specific methods of automatically obtaining keywords in PHP_PHP Tutorial

We are working on itNowadays CMS comes with a collection function. Content and titles are relatively easy to process, but in most cases it is difficult to extract keywords. Therefore, automatically obtaining keywords has become a "traditional problem" in current PHP-based CMS.

So how can PHP automatically obtain keywords? The main steps can be divided into the following three steps:

PHP automatically obtains keywords 1. Use the word segmentation algorithm to divide the title into and content are segmented respectively, and keywords and frequencies are extracted

In the word segmentation stage of content, the two main algorithms currently are ICTCLAS of the Chinese Academy of Sciences and the Hidden Markov Model. But both of them are too high-end, have certain thresholds, and both only support C++/JAVA. There are currently two recommended PSCWS and HTTPCWS based on PHP.

SCWS released the official version 1.0.0 on 2008-03-08, and now the latest version has reached 1.0.4. PSCWS is its PHP version. HTTPCWS was developed by Zhang Yan and was previously called PHPCWS.

PHPCWS first uses the API of "ICTCLAS 3.0 Shared Version Chinese Word Segmentation Algorithm" for initial word segmentation processing, and then uses the self-written "Reverse Maximum Matching Algorithm" to segment and merge words, and adds a punctuation mark filtering function , get the word segmentation result. Currently only Linux/Unix systems are supported.

PHP automatically obtains keyword 2, compares the extraction results with the existing thesaurus, and gets the keywords that best comply with the rules

The main thing here is to look at the thesaurus , we can define our own lexicon, or we can use an existing mature lexicon.

PHP automatically obtains keyword 3, and then compares the two sets of keywords to get the keyword that best matches the current content

At this stage, it is the specific situation. analyzed. Currently, all PHP CMSs have their own keyword extraction systems. Among them, the word segmentation source code of DEDECMS is the most widely circulated on the Internet. I have also tested it on my POPCMS, and the effect is very good. However, the frequency of meaningless words like "we" being extracted and listed as keywords is too high. , and sometimes HTML with spaces is even used as keywords, which needs improvement urgently. But as an auxiliary function, it is already very good.
In addition, PHPCMS and DISCUZ’s PHP function of automatically obtaining keywords is also very powerful.

http://www.bkjia.com/PHPjc/446232.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446232.htmlTechArticleThe current CMS we are working on all has its own collection function, and the content and title are relatively easy to handle, but In most cases, keywords are difficult to extract. So automatically obtaining keywords becomes the current...