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

问题描述

我想将网页抓取到4列csv文件中，并且某些表数据不包含任何数据，我想将其写为空单元格值，而不是用.text跳过它。我也尝试使用.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，以获取<td>是否具有<a href>，然后附加<a>标签数据，附加<td>中的内容，但写为空如果<td>没有数据，则返回（或文本“ None”）值。 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>

我希望输出显示

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

我已经测试并在stackoverflow上查找示例了几个星期了：（，请帮助。在此先感谢！

解决方法

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)

编写此data.csv：

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