python之Beautiful Soup 输出中的正则表达式

我正在尝试从 HTML 页面获取行，由 BS 处理，包含
“十亿”这个词。但是我得到的是空列表.....顺便说一句，这些行介于
<li>标签，我尝试使用 soup.findAll("<li>", {"class": "tabcontent"})

但它也给了我一个空列表。

import requests 
from bs4 import BeautifulSoup 
import re 
 
url = 'http://www.worldstopexports.com/united-states-top-10-exports/' 
 
header = { 
    "User-Agent": "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.75 Safari/537.36", 
    "X-Requested-With": "XMLHttpRequest" 
} 
 
page = requests.get (url, headers=header) 
 
soup = BeautifulSoup (page.text, 'lxml') 
 
table = soup.find_all (class_='tabcontent')[0].text 
 
print(re.findall(r'^.*? billion', table)) 
 
print(table) 
 
 
 
Machinery including computers: US$201.7 billion (13% of total exports) 
Electrical machinery, equipment: $174.2 billion (11.3%) 
Mineral fuels including oil: $138 billion (8.9%) 
Aircraft, spacecraft: $131.2 billion (8.5%) 
Vehicles: $130.1 billion (8.4%) 
Optical, technical, medical apparatus: $83.6 billion (5.4%) 
Plastics, plastic articles: $61.5 billion (4%) 
Gems, precious metals: $60.4 billion (3.9%) 
Pharmaceuticals: $45.1 billion (2.9%) 
Organic chemicals: $36.2 billion (2.3%) 

请您参考如下方法:

您可以使用 select() 首先获取选项卡，然后获取 li 子项和文本:

# ... right under soup = BeautifulSoup (page.text, 'lxml') ... 
# select the first tab 
tab = soup.select('div.tabcontent')[0] 
 
# select its items 
items = [text  
    for item in tab.select('li')  
    for text in [item.text]  
    if "billion" in text] 
print(items) 

这产生

['Machinery including computers: US$201.7 billion (13% of total exports)', 'Electrical machinery, equipment: $174.2 billion (11.3%)', 'Mineral fuels including oil: $138 billion (8.9%)', 'Aircraft, spacecraft: $131.2 billion (8.5%)', 'Vehicles: $130.1 billion (8.4%)', 'Optical, technical, medical apparatus: $83.6 billion (5.4%)', 'Plastics, plastic articles: $61.5 billion (4%)', 'Gems, precious metals: $60.4 billion (3.9%)', 'Pharmaceuticals: $45.1 billion (2.9%)', 'Organic chemicals: $36.2 billion (2.3%)']