Application and examples of greedy principle of PHP regular expressions

Regular expressions are a powerful pattern matching tool that can be used to find, replace, and verify specific patterns in strings. In PHP, the greedy principle of regular expressions refers to the characteristic of getting as many matches as possible when matching. This article will introduce the greedy principle of regular expressions in PHP and provide some sample code to illustrate its usage.

1. Overview of the Greedy Principle
   The greedy principle in regular expressions means to match as many characters as possible to satisfy a given pattern. When using a greedy quantifier, the regular expression engine will try to match as many characters as possible until it can no longer match. This may cause matches to exceed the expected range.

2. Sample code description
   Next, we will use some sample code to illustrate the application of the greedy principle of regular expressions in PHP.

Example 1: Matching HTML Tags
Suppose we have a string containing HTML tags and we want to extract all tag content in it. Here is a sample code:

$html = '<div class="container"><h1>Title</h1><p>Paragraph</p></div>';

preg_match_all('/<.*?>/',