将id属性插入到字符串中的下一个<p>标记中

from bs4 import BeautifulSoup

def insert_id_to_p_tag(html_string, id_value):
    # 使用BeautifulSoup解析HTML字符串
    soup = BeautifulSoup(html_string, 'html.parser')
    
    # 找到第一个<p>标记
    p_tag = soup.find('p')
    
    # 在<p>标记中插入id属性
    p_tag['id'] = id_value
    
    # 将修改后的HTML标记重新组合成字符串
    modified_html = str(soup)
    
    return modified_html

html_string = '<div><p>This is the first paragraph.</p><p>This is the second paragraph.</p></div>'
id_value = 'my-id'

modified_html = insert_id_to_p_tag(html_string, id_value)
print(modified_html)

<div><p id="my-id">This is the first paragraph.</p><p>This is the second paragraph.</p></div>