PYTHON - BEAUTIFULSOUP 如何将空 TD(表数据)刮取为空值而不是跳过它

Question

我想将网页抓取到 4 列 csv 文件中，并且某些表数据不包含数据，我想将其写为空单元格值，而不是使用 .text 跳过它。 。我还尝试使用.string 但它给了我 TypeError: can only concatenate str (not "NoneType") to str 我还想设置一个动态查找来获取 if <td>有<a href>然后附加 <a>如果没有标记数据，请附加 <td> 中的内容但如果 <td> 则写为空(或文本“无”)值没有数据。 您可以在下面看到 HTML 示例。

from urllib.request import urlopen as uReq
from bs4 import BeautifulSoup as soup

my_url = 'https://www.example.com'

# opening up connection, grabbing the page
uClient = uReq(my_url)

page_soup = soup(uClient.read(), "lxml")
uClient.close()

# containers = page_soup.find("table", {"class": "typetable"}).find_all("tr",{"class":"typetable"})
# container = containers[0]

containers = page_soup.find_all("tr", {"class": "typetable"})

# print(containers.td)

tds = []

out_filename = "output.csv"

headers = "Parameter,Type_Value,Cardinality,Description \n"

f = open(out_filename, "w")
f.write(headers)

parameter = []
type_value = []
cardinality = []
description = []

for container in containers:

    parameter = container.findAll('td')[0].text
 
    type_value = container.find_all('td')[1].text

    cardinality = container.find_all('td')[2].text

    description = container.find_all('td')[3].text


    print("parameter: " + parameter + "\n")
    print("type_value: " + type_value + "\n")
    print("cardinality: " + cardinality + "\n")
    print("description: " + description + "\n")

    #f.write(parameter + ', ' + type_value + ', ' + cardinality + ', "' + description + ' "\n')
    f.write(f'{parameter},{str(type_value)},{cardinality},"{description}"\n')

f.close()

这是一个示例 html:

<tr class="typetable">
  <td>Data 1&nbsp;</td>
  <td>Data 2&nbsp;</td>
  <td>&nbsp;</td>
  <td>Data 4&nbsp;</td>
</tr>
<tr class="typetable">
  <td>Data 10&nbsp;</td>
  <td>
     <a href="#2ndPage">2ndPage</a>"&nbsp;"
  </td>
  <td>Data 3&nbsp;</td>
  <td>&nbsp;</td>
</tr>

我想要显示输出

Parameter,Type_Value,Cardinality,Description
Data 1,Data 2,,"Data 4"
Data 1,2ndPage,Data 3,

我已经在 stackoverflow 上测试和查找示例几个星期了:(，请帮忙。提前致谢!

Answer 1

您可以使用此脚本从表中提取数据:

import csv
from bs4 import BeautifulSoup


txt = '''<tr class="typetable">
  <td>Data 1&nbsp;</td>
  <td>Data 2&nbsp;</td>
  <td>&nbsp;</td>
  <td>Data 4&nbsp;</td>
</tr>
<tr class="typetable">
  <td>Data 10&nbsp;</td>
  <td>
     <a href="#2ndPage">2ndPage</a>"&nbsp;"
  </td>
  <td>Data 3&nbsp;</td>
  <td>&nbsp;</td>
</tr>'''

soup = BeautifulSoup(txt, 'html.parser')

all_data = []
for row in soup.select('tr.typetable'):
    tds = [td.a.get_text(strip=True) if td.a else td.get_text(strip=True) for td in row.select('td')]
    all_data.append(tds)


with open('data.csv', 'w', newline='') as csvfile:
    writer = csv.writer(csvfile, delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL)
    writer.writerow(['Parameter','Type_Value','Cardinality','Description'])
    for row in all_data:
        writer.writerow(row)

写入data.csv:

Parameter,Type_Value,Cardinality,Description
Data 1,Data 2,,Data 4
Data 10,2ndPage,Data 3,