PHP使用similar_text()函数计算字符串相似度

小咪咪 2023-03-01 13:46 2阅读 0赞

<?php
    class LCS { 
        var $str1;
        var $str2;
        var $c = array();
        /*返回串一和串二的最长公共子序列*/
        function getLCS($str1, $str2, $len1 = 0, $len2 = 0) { 
            $this->str1 = $str1;
            $this->str2 = $str2;
            if ($len1 == 0) $len1 = strlen($str1);
            if ($len2 == 0) $len2 = strlen($str2);
            $this->initC($len1, $len2);
            return $this->printLCS($this->c, $len1 - 1, $len2 - 1);
        }
        /*返回两个串的相似度*/
        function getSimilar($str1, $str2) { 
            $len1 = strlen($str1);
            $len2 = strlen($str2);
            $len = strlen($this->getLCS($str1, $str2, $len1, $len2));
            return $len * 2 / ($len1 + $len2);
        }
        function initC($len1, $len2) { 
            for ($i = 0; $i < $len1; $i++) $this->c[$i][0] = 0;
            for ($j = 0; $j < $len2; $j++) $this->c[0][$j] = 0;
            for ($i = 1; $i < $len1; $i++) { 
                for ($j = 1; $j < $len2; $j++) { 
                    if ($this->str1[$i] == $this->str2[$j]) { 
                        $this->c[$i][$j] = $this->c[$i - 1][$j - 1] + 1;
                    } else if ($this->c[$i - 1][$j] >= $this->c[$i][$j - 1]) { 
                        $this->c[$i][$j] = $this->c[$i - 1][$j];
                    } else { 
                        $this->c[$i][$j] = $this->c[$i][$j - 1];
                    }
                }
            }
        }
        function printLCS($c, $i, $j) { 
            if ($i == 0 || $j == 0) { 
                if ($this->str1[$i] == $this->str2[$j]) return $this->str2[$j];
                else return "";
            }
            if ($this->str1[$i] == $this->str2[$j]) { 
                return $this->printLCS($this->c, $i - 1, $j - 1).$this->str2[$j];
            } else if ($this->c[$i - 1][$j] >= $this->c[$i][$j - 1]) { 
                return $this->printLCS($this->c, $i - 1, $j);
            } else { 
                return $this->printLCS($this->c, $i, $j - 1);
            }
        }
    }
    
    $lcs = new LCS();
    //返回最长公共子序列
    $lcs->getLCS("hello word","hello china");
    //返回相似度
    echo similar_text("abc","ABC"); // 0
    echo similar_text("abc","cba"); // 1
    echo similar_text("吉林禽业公司火灾已致112人遇难","吉林宝源丰禽业公司火灾已致112人遇难"); // 42
    echo $lcs->getSimilar("吉林禽业公司火灾已致112人遇难","吉林宝源丰禽业公司火灾已致112人遇难"); // 0.90322580645161
    $str = new LCS();
    similar_text('太乙真人','太二真人',$percent);
    echo number_format($percent,0),"\n"; // 83
    echo $str->getSimilar('太乙真人','太二真人'),"\n"; // 0.83333333333333
    echo number_format($str->getSimilar('太乙真人','太二真人'),2); // 0.83
    ?>

**原文链接：**  
[https://www.jb51.net/article/32901.htm][https_www.jb51.net_article_32901.htm]  
**参考其他文章：**

*  [https://blog.csdn.net/iteye\_5904/article/details/82041955][https_blog.csdn.net_iteye_5904_article_details_82041955]
 *  [https://www.cnblogs.com/zhaobijin/p/5813330.html][https_www.cnblogs.com_zhaobijin_p_5813330.html]

[https_www.jb51.net_article_32901.htm]: https://www.jb51.net/article/32901.htm
[https_blog.csdn.net_iteye_5904_article_details_82041955]: https://blog.csdn.net/iteye_5904/article/details/82041955
[https_www.cnblogs.com_zhaobijin_p_5813330.html]: https://www.cnblogs.com/zhaobijin/p/5813330.html