search
HomeBackend DevelopmentPHP TutorialGlobal regular expression matching and matching array elements in PHP (detailed examples)

In the previous article, I brought you "The exciting regular expression basis of PHP (detailed illustration)", which briefly introduced some of the regular expressions. Basic knowledge, in this article we will continue to look at some common functions of regular expressions. I hope it will be helpful to everyone!

Global regular expression matching and matching array elements in PHP (detailed examples)

In the previous article, we introduced some basic definitions of regular expressions and the basic application of the preg_match() function, using regular expressions The main purpose is to achieve powerful functions through simple methods. In order to be simple, effective and powerful, the regular expression rules are complicated, and it is even more difficult to construct correct and effective regular expressions, so using only one preg_match() function is not enough. .

Regular expressions are an important and complex technology when processing text data. Some text editors also use regular expressions to implement high-level "search/replace" functions. If you want to implement more functions, you need to know more functions. Next, let's take a look at more function knowledge about regular expressions.

<strong><span style="font-size: 18px;">preg_match_all()</span></strong><strong><span style="font-size: 18px;"></span></strong>##Function

Before we only introduced the basic function of

preg_match() function, there is also a function in PHP that is very similar to the preg_match() function ——preg_match_all(), this function can search for all results in the string that can match the regular expression.

The syntax format of this function is as follows:

preg_match_all($pattern, $subject [, &$matches [, $flags = PREG_PATTERN_ORDER [, $offset = 0 ]]])

It should be noted that:


##$pattern

represents the pattern to be searched, and also It is a defined regular expression; $subject indicates the string to be searched; $matches indicates that the optional parameter is a multi-dimensional array used to store all matching results. The array is sorted by $flags Specify; $offset represents optional parameters, $offset is used to start searching from the specified position in the target string, and its unit is bytes. $flags represents optional parameters, which can be used in combination with the following tags,

  • ##PREG_PATTERN_ORDER

    <strong></strong>

    The results are sorted as $matches[0] saves all matches of the complete pattern, $matches[1] saves all matches of the first subgroup, and so on.

  • PREG_SET_ORDER

    <strong></strong>

    The results are sorted into $matches[0] including the first match All matches (including subgroups) obtained, $matches[1] is an array containing all matches (including subgroups) obtained by the second match, and so on.

  • PREG_OFFSET_CAPTURE

    <strong></strong>

    If this tag is passed, each found match is returned will increase its offset relative to the target string. Note that this will change each matching result string element in
  • $matches
so that it becomes a matching result string whose 0th element is the matching result string and the first element is the offset of the matching result string in the subject. Shift amount.

You cannot use PREG_PATTERN_ORDER

and

PREG_SET_ORDER at the same time. The preg_match_all() function can return the number of matches of $pattern (possibly 0), and return ## if an error occurs. #FALSE. Next, let’s look at the application of the preg_match_all() function through an example to match a string. The example is as follows: <pre class='brush:php;toolbar:false;'>&lt;?php $subject = &quot;abcdefghijkdefabcedfdefxyzdef&quot;; $pattern_1 = &amp;#39;/(def)(abc)/&amp;#39;; $num_1 = preg_match_all($pattern_1, $subject, $matches_1,PREG_PATTERN_ORDER); echo &quot;&lt;pre class=&quot;brush:php;toolbar:false&quot;&gt;&quot;; var_dump($matches_1); var_dump($num_1); $pattern_2 = &amp;#39;/(def)(abc)/&amp;#39;; $num_2 = preg_match_all($pattern_2, $subject, $matches_2,PREG_OFFSET_CAPTURE, 3); var_dump($matches_2); var_dump($num_2); ?&gt;</pre>Output result:

From the above example, we have completed matching a string through the preg_match_all() function. Global regular expression matching can be completed through the application of the preg_match_all() function.

Global regular expression matching and matching array elements in PHP (detailed examples)Then let’s take a look at how to detect array elements that match a given pattern. This is when the preg_grep() function is used.

preg_grep()

<strong><span style="font-size: 18px;"></span>Function</strong>Use regular expressions In addition to matching strings, you can also match elements in arrays. The preg_grep() function in PHP can search all elements in an array and return an array of all elements that match the regular expression. The syntax format of this function is as follows:

preg_grep($pattern, $input [, $flags = 0 ])
What needs to be noted is:

$pattern表示要搜索的模式,也就是定义好的正则表达式;$input表示要搜索的数组;$flags表示可选参数,可以设置为 PREG_GREP_INVERT,这时函数会返回数组中与给定模式 $pattern 不匹配的元素组成的数组。perg_grep() 函数将遍历 $input 数组中的每一个元素,让该元素与模式 $pattern 进行匹配,然后将匹配成功或者匹配失败的元素返回。

接下来,我们通过示例来看一下使用 perg_grep() 函数匹配数组中的元素,示例如下:

<?php
    $test_arr = array(
        &#39;PHP中文网&#39;,
        &#39;http://www.php.cn/&#39;,
        &#39;php教程&#39;,
        &#39;abcdefg&#39;
    );
    $preg = &#39;/^[a-z]/&#39;;
    $preg_arr_1 = preg_grep($preg, $test_arr);
    $preg_arr_2 = preg_grep($preg, $test_arr, PREG_GREP_INVERT);
    echo &#39;<pre class="brush:php;toolbar:false">&#39;;
    var_dump($preg_arr_1);
    var_dump($preg_arr_2);
?>

输出结果:

Global regular expression matching and matching array elements in PHP (detailed examples)

上述示例便是通过preg_grep() 函数匹配数组中的元素。

大家如果感兴趣的话,可以点击《PHP视频教程》、《正则表达式手册》进行更多关于PHP和正则表达式知识的学习。

The above is the detailed content of Global regular expression matching and matching array elements in PHP (detailed examples). For more information, please follow other related articles on the PHP Chinese website!

Statement
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
The Continued Use of PHP: Reasons for Its EnduranceThe Continued Use of PHP: Reasons for Its EnduranceApr 19, 2025 am 12:23 AM

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python: Exploring Their Similarities and DifferencesPHP and Python: Exploring Their Similarities and DifferencesApr 19, 2025 am 12:21 AM

PHP and Python are both high-level programming languages ​​that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP and Python: Different Paradigms ExplainedPHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: A Deep Dive into Their HistoryPHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Choosing Between PHP and Python: A GuideChoosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP and Frameworks: Modernizing the LanguagePHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHP's Impact: Web Development and BeyondPHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values ​​and handle functions that may return null values.

See all articles

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

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

VSCode Windows 64-bit Download

VSCode Windows 64-bit Download

A free and powerful IDE editor launched by Microsoft

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

Powerful PHP integrated development environment