Home php教程 php手册 PHP中计算字符串相似度的函数代码

PHP中计算字符串相似度的函数代码

Jun 13, 2016 am 11:55 AM
in php text code function string Every time of resemblance calculate

similar_text — 计算两个字符串的相似度
int similar_text ( string $first , string $second [, float &$percent ] )
$first 必需。规定要比较的第一个字符串。
$second 必需。规定要比较的第二个字符串。
$percent 可选。规定供存储百分比相似度的变量名。

两个字符串的相似程度计算依据 Oliver [1993] 的描述进行。注意该实现没有使用 Oliver 虚拟码中的堆栈,但是却进行了递归调用,这个做法可能会导致整个过程变慢或变快。也请注意,该算法的复杂度是 O(N**3),N 是最长字符串的长度。

比如我们想找字符串abcdefg和字符串aeg的相似度:

复制代码 代码如下:


$first = "abcdefg";
$second = "aeg";
echo similar_text($first, $second);结果输出3.如果想以百分比显示,则可使用它的第三个参数,如下:
$first = "abcdefg";
$second = "aeg";
similar_text($first, $second, $percent);
echo $percent;



similar_text函数的使用及实现过程。similar_text() 函数主要是用来计算两个字符串的匹配字符的数目,也可以计算两个字符串的相似度(以百分比计)。与 similar_text() 函数相比,我们今天要介绍的 levenshtein() 函数更快。不过,similar_text() 函数能通过更少的必需修改次数提供更精确的结果。在追求速度而少精确度,并且字符串长度有限时可以考虑使用 levenshtein() 函数。

使用说明

先看手册上 levenshtein() 函数的说明:

levenshtein() 函数返回两个字符串之间的 Levenshtein 距离。

Levenshtein 距离,又称编辑距离,指的是两个字符串之间,由一个转换成另一个所需的最少编辑操作次数。许可的编辑操作包括将一个字符替换成另一个字符,插入一个字符,删除一个字符。

例如把 kitten 转换为 sitting:

sitten (k→s)
sittin (e→i)
sitting (→g)levenshtein() 函数给每个操作(替换、插入和删除)相同的权重。不过,您可以通过设置可选的 insert、replace、delete 参数,来定义每个操作的代价。

语法:

levenshtein(string1,string2,insert,replace,delete)

参数 描述

•string1 必需。要对比的第一个字符串。
•string2 必需。要对比的第二个字符串。
•insert 可选。插入一个字符的代价。默认是 1。
•replace 可选。替换一个字符的代价。默认是 1。
•delete 可选。删除一个字符的代价。默认是 1。
提示和注释

•如果其中一个字符串超过 255 个字符,levenshtein() 函数返回 -1。
•levenshtein() 函数对大小写不敏感。
•levenshtein() 函数比 similar_text() 函数更快。不过,similar_text() 函数提供需要更少修改的更精确的结果。
例子

复制代码 代码如下:


echo levenshtein("Hello World","ello World");
echo "
";
echo levenshtein("Hello World","ello World",10,20,30);
?>


输出: 1 30
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
3 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

CakePHP Project Configuration CakePHP Project Configuration Sep 10, 2024 pm 05:25 PM

In this chapter, we will understand the Environment Variables, General Configuration, Database Configuration and Email Configuration in CakePHP.

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

CakePHP Date and Time CakePHP Date and Time Sep 10, 2024 pm 05:27 PM

To work with date and time in cakephp4, we are going to make use of the available FrozenTime class.

CakePHP File upload CakePHP File upload Sep 10, 2024 pm 05:27 PM

To work on file upload we are going to use the form helper. Here, is an example for file upload.

CakePHP Routing CakePHP Routing Sep 10, 2024 pm 05:25 PM

In this chapter, we are going to learn the following topics related to routing ?

Discuss CakePHP Discuss CakePHP Sep 10, 2024 pm 05:28 PM

CakePHP is an open-source framework for PHP. It is intended to make developing, deploying and maintaining applications much easier. CakePHP is based on a MVC-like architecture that is both powerful and easy to grasp. Models, Views, and Controllers gu

How To Set Up Visual Studio Code (VS Code) for PHP Development How To Set Up Visual Studio Code (VS Code) for PHP Development Dec 20, 2024 am 11:31 AM

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

CakePHP Creating Validators CakePHP Creating Validators Sep 10, 2024 pm 05:26 PM

Validator can be created by adding the following two lines in the controller.

See all articles