正则多结果匹配需求：提取title类名及子li的name与src属性值

Hey there! Let's break down how to solve your problem with regular expressions. First, I'll assume you're working with HTML-like content where elements with the title class are followed by a <ul> containing your target <li> elements (since you mentioned child li elements). Let's start with a sample input to ground our solution:

<div class="title">Fruits Collection</div>
<ul>
  <li name="red_apple" src="/assets/apple-red.png">Crisp Red Apple</li>
  <li name="yellow_banana" src="/assets/banana-yellow.png">Sweet Yellow Banana</li>
</ul>
<div class="title">Vegetable Picks</div>
<ul>
  <li name="orange_carrot" src="/assets/carrot-orange.png">Crunchy Orange Carrot</li>
  <li name="green_spinach" src="/assets/spinach-green.png">Nutritious Green Spinach</li>
  <li name="purple_eggplant" src="/assets/eggplant-purple.png">Rich Purple Eggplant</li>
</ul>

Step 1: The Regex Pattern #

We'll use a pattern that first captures the text inside the title class element, then extracts the name and src attributes from every child <li>. Here's the pattern (tweaked for flexibility with whitespace):

<div class="title">(.*?)<\/div>\s*<ul>\s*(?:<li name="(.*?)" src="(.*?)".*?<\/li>\s*)*<\/ul>

Let's break down what each part does:

• <div class="title">(.*?)<\/div>: Captures the text inside the title element (group 1) — the .*? is a non-greedy match to stop at the closing </div>.
• \s*: Matches any amount of whitespace (newlines, spaces, tabs) to handle messy formatting.
• <ul>\s*: Matches the opening unordered list tag and any following whitespace.
• (?:<li name="(.*?)" src="(.*?)".*?<\/li>\s*)*: A non-capturing group that repeats for every <li>:
  • name="(.*?)": Captures the name attribute value (group 2).
  • src="(.*?)": Captures the src attribute value (group 3).
  • .*?<\/li>: Matches the rest of the li content until the closing tag.

Step 2: Implementing the Pattern (Python Example) #

Since regex engines handle repeated capture groups differently, here's a practical Python implementation that extracts all title-name-src pairs correctly:

import re

# Your input content
content = """
<div class="title">Fruits Collection</div>
<ul>
  <li name="red_apple" src="/assets/apple-red.png">Crisp Red Apple</li>
  <li name="yellow_banana" src="/assets/banana-yellow.png">Sweet Yellow Banana</li>
</ul>
<div class="title">Vegetable Picks</div>
<ul>
  <li name="orange_carrot" src="/assets/carrot-orange.png">Crunchy Orange Carrot</li>
  <li name="green_spinach" src="/assets/spinach-green.png">Nutritious Green Spinach</li>
  <li name="purple_eggplant" src="/assets/eggplant-purple.png">Rich Purple Eggplant</li>
</ul>
"""

# First, match each title + ul block
title_block_pattern = re.compile(r'<div class="title">(.*?)<\/div>\s*<ul>(.*?)<\/ul>', re.DOTALL)

for match in title_block_pattern.finditer(content):
    title_name = match.group(1).strip()
    print(f"📋 Title: {title_name}")
    
    # Now extract li name and src from the captured ul content
    li_pattern = re.compile(r'<li name="(.*?)" src="(.*?)".*?<\/li>')
    li_matches = li_pattern.findall(match.group(2))
    
    for name, src in li_matches:
        print(f"  - Name: *{name}*, Src: `{src}`")

Step 3: Key Notes & Caveats #

• Format Flexibility: If your HTML uses single quotes for attributes (e.g., name='apple'), adjust the regex to use ' instead of ".
• Tag Variations: If your title class is on a different tag (like <h2> instead of <div>), update the pattern's opening/closing tags.
• Regex Limitation: Regular expressions aren't designed for nested HTML structures. If your <li> elements contain nested tags or the HTML is heavily malformed, you'll get better results with an HTML parser like Python's BeautifulSoup or JavaScript's Cheerio.

内容的提问来源于stack exchange，提问作者MGR