regular expression tutorial

When learning PHP, you may encounter the problem of judging PHP regular expressions, here will introduce the solution of the PHP regular expression problem, here to share with you. In some query sites and search engines, it is often used to determine whether a string is a standard IP address. For example, in Baidu search for an IP address, will displa

$string='April15,2003';$pattern='/(\w+)(\d+),(\d+)/i';$replacement='${1},${3}';echo preg_replace($pattern,$replacement,$string);?> The result of this expression is april1,2003Cause: (\w+) can match April15 completely, but because (\d+) is behind (\w+), in order to be able to match defined rules, (\w+) matches April1, (\d+) matches 5You can change the expression to avoid this situation such as:$pattern = '/

PHP Regular Expression Matching Chinese problem analysis, $str = ' People's Republic of China 123456789ABCDEFG ';Echo Preg_match ("/^[u4e00-u9fa5_a-za-z0-9]{3,15}$", $strName); Run the above code and see what the message is?Warning:preg_match (): compilation Failed:pcre does not support L, L, N, p, p, U, u, or X at offset 3 in F:http://www.hzh Uti.com/nokia/5800/on Line 2Originally, the following Perl esc

Php regular expression to get all the image addresses on the page ,. Php regular expression to get all the image addresses on the page ,? Php retrieves all the image addresses on the page: functiongetimages ($ str) {$ match_str () + ([^ rn () ^ $! '| [] {}] * Getting (.gif) | (.jpg) | (.bmp) php

Php uses a regular expression to obtain the image url ,. Php uses a regular expression to obtain the image url. this example describes how php uses a regular expression to obtain the image url. Share it with you for your reference

A regular expression (regular expression) describes a pattern of string matching that can be used to check whether a string contains a seed string, replaces a matching substring, or extracts a substring from a string that matches a condition. Escape matching syntax: "\" + actual character \. * + ? | () {}^ $ [] For e

This article mainly introduces the UTF-8 regular expression how to match Chinese characters, a small partner can refer to determine whether the input content contains illegal characters, please refer to the following code $ Str = "programming"; // if (! Preg_match ("/^ [\ x {4e00}-\ x {9fa5} A-Za-z0-9 _] + $/u", $ str )) // UTF-8 Chinese characters, letters, numbers, underscores,

The next step is to make a small example of a reptile with embarrassing hundred. But before you do that, start by detailing the regular expressions in Python. Regular expressions play a role in Python reptiles, like the roster used by teachers to roll names, and are essential weapons of God. The basis of regular expressions 1.1. Introduction to the concept A

Use of the regular expression processing function get_matches based on curl data collection. According to the first two blog posts: the single-page collection function get_html based on curl data collection, the use of the single-page parallel collection function get_htmls based on curl data collection is ready. Based on the first two blog posts: Use of the single page collection function get_html based on

Web crawl information (PHP regular expression, PHP operation Excel) 1. Description of the problem To capture the information you need on a fixed web page and store it in a tabular format. I took a list of wustoj to practice, address: Wustoj 2. Ideas Web page itself simply learn PHP, just use it to do something, my idea is this: (1) View the source code of the webpage and save it in the file. (2) write the

The PHP regular expression extracts the href address from the html hyperlink. Sometimes we need to filter or extract external links of html strings. next I will introduce an href address program that uses PHP regular expressions to extract the href address from html hyperlinks. When using php, we need to filter or extract external links of html strings. next I wi

Common characters A common character consists of all the print and non-print characters that are not explicitly specified as metacharacters. This includes all uppercase and lowercase letter characters, all numbers, all punctuation marks, and some symbols. The simplest regular expression is a single normal character that can match the character itself in the searched string. For example, the single-Charact

Preg_match: the regular expression used to determine the user name. Solution to the regular expression used to determine the user name for problem: preg_match (^ s * $ | ^ c: \ con $ | [%, * st, double quotation marks, space characters, tabs, problems Judge the regular

Ask a question about the regular expression ~ I want to develop a News collection program and use curl to collect HTML code. I want to use a regular expression to separate the data I need, for example: lt; table nbsp; cellspacing0 nbsp; cellpadding0 nbsp; bgcolor # FFCCCC nbsp; ask a question about

Use PHP for simple regular expression replacement to find a simple regular expression code nbsp; namehello1 nbsp; version2012code nbsp; name123 nbsp; version2012code nbsp; name code nbsp; version2012 replace the regular expression