Python：如何使用（BeautifulSoup）访问和迭代div类元素列表

时间：2018-06-05 23:32:04

标签： python loops beautifulsoup

我正在使用BeautifulSoup解析有关汽车生产的数据（另请参阅我的first question）：

from bs4 import BeautifulSoup
import string

html = """
<h4>Production Capacity (year)</h4>
    <div class="profile-area">
      Vehicle 1,140,000 units /year
    </div>
<h4>Output</h4>
    <div class="profile-area">
      Vehicle 809,000 units ( 2016 ) 
    </div>
    <div class="profile-area">
      Vehicle 815,000 units ( 2015 ) 
    </div>
    <div class="profile-area">
      Vehicle 836,000 units ( 2014 ) 
    </div>
    <div class="profile-area">
      Vehicle 807,000 units ( 2013 ) 
    </div>
    <div class="profile-area">
      Vehicle 760,000 units ( 2012 ) 
    </div>
    <div class="profile-area">
      Vehicle 805,000 units ( 2011 ) 
    </div>
"""
soup = BeautifulSoup(html, 'lxml')

for item in soup.select("div.profile-area"):
  produkz = item.text.strip()
  produkz = produkz.replace('\n',':')

  prev_h4 = str(item.find_previous_sibling('h4'))
  if "Models" in prev_h4:
    models=produkz
  else:
    models=""

  if "Capacity" in prev_h4:
    capacity=produkz
  else:
    capacity=""

  if "( 2015 )" in produkz:
    prod15=produkz
  else:
    prod15=""
  if "( 2016 )" in produkz:
    prod16=produkz
  else:
    prod16=""
  if "( 2017 )" in produkz:
    prod17=produkz
  else:
    prod17=""

  print(models+';'+capacity+';'+prod15+';'+prod16+';'+prod17)

我的问题是，所有匹配的HTML事件（“div.profile-area”）的下一个循环都会覆盖我的结果：

;Vehicle 1,140,000 units /year;;;;;;
;;;;;;Vehicle 809,000 units ( 2016 );
;;;;;Vehicle 815,000 units ( 2015 );;
;;;;Vehicle 836,000 units ( 2014 );;;
;;;Vehicle 807,000 units ( 2013 );;;;
;;Vehicle 760,000 units ( 2012 );;;;;
;;;;;;;

我想要的结果是：

;Vehicle 1,140,000 units /year;Vehicle 760,000 units ( 2012 );Vehicle 807,000 units ( 2013 );Vehicle 836,000 units ( 2014 );Vehicle 815,000 units ( 2015 );Vehicle 809,000 units ( 2016 );

如果你能给我一个更好的方法来构建我的代码，我会很高兴的。提前谢谢。

2 个答案:

答案 0 :(得分：1)

这是我的解决方案，您需要处理每个元素标记并相应地解析它。我进一步解决了您的问题，并提供了一种更灵活的方式来访问每个数据值。希望它有所帮助。

import re

from bs4 import BeautifulSoup

html_doc = """
<h4>Production Capacity (year)</h4>
    <div class="profile-area">
    Vehicle 1,140,000 units /year
    </div>
<h4>Output</h4>
    <div class="profile-area">
    Vehicle 809,000 units ( 2016 ) 
    </div>
    <div class="profile-area">
    Vehicle 815,000 units ( 2015 ) 
    </div>
    <div class="profile-area">
    Vehicle 836,000 units ( 2014 ) 
    </div>
    <div class="profile-area">
    Vehicle 807,000 units ( 2013 ) 
    </div>
    <div class="profile-area">
    Vehicle 760,000 units ( 2012 ) 
    </div>
    <div class="profile-area">
    Vehicle 805,000 units ( 2011 ) 
    </div>"""

soup = BeautifulSoup(html_doc, 'html.parser')
h4_elements = soup.find_all('h4')
profile_areas = soup.find_all('div', attrs={'class': 'profile-area'})
print('\n')
print("++++++++++++++++++++++++++++++++++++")
print("Element counts")
print("++++++++++++++++++++++++++++++++++++")
print("Total H4: {}".format(len(h4_elements)))
print("++++++++++++++++++++++++++++++++++++")
print("Total profile-area: {}".format(len(profile_areas)))
print("++++++++++++++++++++++++++++++++++++")
print('\n')

for i in h4_elements:
    print("++++++++++++++++++++++++++++++++++++")
    print(i.text.rstrip().lstrip())
    print("++++++++++++++++++++++++++++++++++++")
    del profile_areas[0]
    for j in profile_areas:
        raw = re.sub('[^A-Za-z0-9]+', ' ', j.text.replace(',','').lstrip().rstrip())
        raw = raw.rstrip()
        el = raw.split(' ')

        print('Type: {} '.format(el[0]))
        print('Sold: {} {} '.format(el[1], el[2]))
        print('Year: {} '.format(el[3]))
        print("++++++++++++++++++++++++++++++++++++")

输出如下：

 ++++++++++++++++++++++++++++++++++++
Production Capacity (year)
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 809000 units 
Year: 2016 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 815000 units 
Year: 2015 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 836000 units 
Year: 2014 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 807000 units 
Year: 2013 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 760000 units 
Year: 2012 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 805000 units 
Year: 2011 
++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++
Output
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 815000 units 
Year: 2015 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 836000 units 
Year: 2014 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 807000 units 
Year: 2013 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 760000 units 
Year: 2012 
++++++++++++++++++++++++++++++++++++
Type:Vehicle 
Sold: 805000 units 
Year: 2011 
++++++++++++++++++++++++++++++++++++

答案 1 :(得分：0)

我建议你将每个条目存储在字典中，然后你可以在最后轻松提取你想要的字段（你似乎不想要2011年？）：

NA

这会显示：

from bs4 import BeautifulSoup
import re

html = """
<h4>Production Capacity (year)</h4>
    <div class="profile-area">
      Vehicle 1,140,000 units /year
    </div>
<h4>Output</h4>
    <div class="profile-area">
      Vehicle 809,000 units ( 2016 ) 
    </div>
    <div class="profile-area">
      Vehicle 815,000 units ( 2015 ) 
    </div>
    <div class="profile-area">
      Vehicle 836,000 units ( 2014 ) 
    </div>
    <div class="profile-area">
      Vehicle 807,000 units ( 2013 ) 
    </div>
    <div class="profile-area">
      Vehicle 760,000 units ( 2012 ) 
    </div>
    <div class="profile-area">
      Vehicle 805,000 units ( 2011 ) 
    </div>
"""

soup = BeautifulSoup(html, 'lxml')
units = {}

for item in soup.find_all(['h4', 'div']):
    if item.name == 'h4':
        for h4 in ['capacity', 'output', 'models']:
            if h4 in item.text.lower():
                break
    elif item.get('class', [''])[0] == 'profile-area':
        vehicle = item.get_text(strip=True)

        if h4 == 'output':
            re_year = re.search(r'\( (\d+) \)', vehicle)

            if re_year:
                year = re_year.group(1)
            else:
                year = 'unknown'

            units[year] = vehicle
        else:
            units[h4] = vehicle

req_fields = ['models', 'capacity', '2012', '2013', '2014', '2015', '2016']            
print(';'.join([units.get(field, '') for field in req_fields]))

正则表达式用于从车辆输入中提取年份。然后将其用作字典中的键。

对于pastebin中的HTML，它给出了：

;Vehicle 1,140,000 units /year;Vehicle 760,000 units ( 2012 );Vehicle 807,000 units ( 2013 );Vehicle 836,000 units ( 2014 );Vehicle 815,000 units ( 2015 );Vehicle 809,000 units ( 2016 )
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