PYTHON-BEAUTIFULSOUP如何将空TD（表数据）作为空值刮取，而不是跳过它

我想将一个网页刮到一个4列csv文件中，其中一些表数据不包含任何数据，我想将其作为空单元格值写入，而不是使用

.text

跳过它。我还尝试使用

.string

，但它给了我

类型错误：只能将str（而不是“NoneType”）连接到str

我还想设置一个动态查找，以获取

是否有

，然后追加

标记数据。如果没有，则追加

中的内容，但如果

没有数据，则写出空值（或文本“无”）。 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()

下面是一个html示例：

<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>

---

我已经在stackoverflow上测试和查找示例数周了：（，请帮助。提前感谢！

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)

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)

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