"""
# ============================================================
# 1. 解析 HTML
# ============================================================
def demo_parse():
"""演示 HTML 解析"""
print("=" * 60)
print("🔧 1. 解析 HTML")
print("=" * 60)
# 使用 lxml 解析器
soup = BeautifulSoup(SAMPLE_HTML, "lxml")
print(f"解析器: {soup.parser_class}")
# 获取标题
title = soup.find("title")
print(f"标题: {title.text}")
# 获取页面编码
meta = soup.find("meta", attrs={"charset": "UTF-8"})
print(f"编码: {meta.get('charset', 'N/A')}")
# ============================================================
# 2. 查找元素
# ============================================================
def demo_find_elements():
"""演示元素查找"""
print("\n" + "=" * 60)
print("🔧 2. 查找元素")
print("=" * 60)
soup = BeautifulSoup(SAMPLE_HTML, "lxml")
# find() - 查找单个元素
print("\n--- find() 查找单个元素 ---")
h1 = soup.find("h1")
print(f"h1 文本: {h1.text}")
# find_all() - 查找所有元素
print("\n--- find_all() 查找所有元素 ---")
products = soup.find_all("div", class_="product-card")
print(f"商品数量: {len(products)}")
for p in products:
name = p.find("h2", class_="product-name").text
price = p.find("span", class_="price").text
print(f" - {name}: {price}")
# 按属性查找
print("\n--- 按属性查找 ---")
links = soup.find_all("a", href=True)
for link in links:
print(f" {link.get('href')}: {link.text}")
# ============================================================
# 3. CSS 选择器
# ============================================================
def demo_css_selector():
"""演示 CSS 选择器"""
print("\n" + "=" * 60)
print("🔧 3. CSS 选择器")
print("=" * 60)
soup = BeautifulSoup(SAMPLE_HTML, "lxml")
# 标签选择器
print("\n--- 标签选择器 ---")
all_links = soup.select("a")
print(f"所有链接数量: {len(all_links)}")
# 类选择器
print("\n--- 类选择器 ---")
nav_links = soup.select(".nav-links a")
for link in nav_links:
print(f" 导航链接: {link.text} → {link.get('href')}")
# 组合选择器
print("\n--- 组合选择器 ---")
prices = soup.select(".product-card .price")
for price in prices:
print(f" 价格: {price.text}")
# 属性选择器
print("\n--- 属性选择器 ---")
product_links = soup.select("a[href^='/product']")
for link in product_links:
print(f" 商品链接: {link.get('href')}")
# 子元素选择器
print("\n--- 子元素选择器 ---")
first_product = soup.select_one(".product-card:first-child .product-name")
if first_product:
print(f" 第一个商品: {first_product.text}")
# ============================================================
# 4. 元素遍历
# ============================================================
def demo_traversal():
"""演示元素遍历"""
print("\n" + "=" * 60)
print("🔧 4. 元素遍历")
print("=" * 60)
soup = BeautifulSoup(SAMPLE_HTML, "lxml")
# 父元素
print("\n--- 父元素遍历 ---")
price = soup.find("span", class_="price")
if price:
parent = price.parent
print(f" price 的父元素: {parent.name}.{parent.get('class', '')}")
# 子元素
print("\n--- 子元素遍历 ---")
product_list = soup.find("div", class_="product-list")
if product_list:
children = [child.name for child in product_list.children if child.name]
print(f" product-list 的子元素: {children}")
# 兄弟元素
print("\n--- 兄弟元素遍历 ---")
h1 = soup.find("h1")
if h1:
next_sibling = h1.find_next_sibling()
if next_sibling:
print(f" h1 的下一个兄弟: {next_sibling.name}.{next_sibling.get('class', '')}")
# ============================================================
# 5. 提取数据
# ============================================================
def demo_extract():
"""演示数据提取"""
print("\n" + "=" * 60)
print("🔧 5. 提取数据")
print("=" * 60)
soup = BeautifulSoup(SAMPLE_HTML, "lxml")
# 提取文本
print("\n--- 提取文本 ---")
footer = soup.find("footer")
if footer:
# get_text() 可以指定分隔符
text = footer.get_text(separator=" | ", strip=True)
print(f" 页脚文本: {text}")
# 提取属性
print("\n--- 提取属性 ---")
product = soup.find("div", class_="product-card")
if product:
data_id = product.get("data-id")
print(f" data-id: {data_id}")
price = product.find("span", class_="price")
currency = price.get("data-currency")
print(f" 货币: {currency}")
# 提取所有链接
print("\n--- 提取所有链接 ---")
all_links = soup.find_all("a", href=True)
link_data = [{"text": a.text, "href": a.get("href")} for a in all_links]
for link in link_data:
print(f" {link['text']}: {link['href']}")
# ============================================================
# 6. lxml XPath
# ============================================================
def demo_lxml_xpath():
"""演示 lxml XPath"""
print("\n" + "=" * 60)
print("🔧 6. lxml XPath")
print("=" * 60)
tree = html.fromstring(SAMPLE_HTML)
# 查找所有商品名
print("\n--- 查找所有商品名 ---")
names = tree.xpath("//h2[@class='product-name']/text()")
for name in names:
print(f" 商品: {name}")
# 查找所有价格
print("\n--- 查找所有价格 ---")
prices = tree.xpath("//span[@class='price']/text()")
for price in prices:
print(f" 价格: {price}")
# 查找所有链接
print("\n--- 查找所有链接 ---")
links = tree.xpath("//a/@href")
for link in links:
print(f" 链接: {link}")
# 查找特定属性的元素
print("\n--- 查找 data-id 属性 ---")
ids = tree.xpath("//div[@data-id]/@data-id")
for id_val in ids:
print(f" ID: {id_val}")
# 组合查询
print("\n--- 组合查询: 商品名和价格 ---")
products = tree.xpath("//div[@class='product-card']")
for product in products:
name = product.xpath(".//h2/text()")[0]
price = product.xpath(".//span[@class='price']/text()")[0]
print(f" {name}: {price}")
# ============================================================
# 7. 主流程
# ============================================================
def main():
print("🚀 Day 127 - BeautifulSoup / lxml 解析：基础用法\n")
demo_parse()
demo_find_elements()
demo_css_selector()
demo_traversal()
demo_extract()
demo_lxml_xpath()
print("\n" + "=" * 60)
print("✅ 基础用法演示完成")
print("=" * 60)
if __name__ == "__main__":
main()