我如何从讨论区提取用户名、post 和日期 post？

Question

我将如何使用 bs4 和 requests 继续这个网络抓取项目？我正在尝试从论坛站点（myfitnesspal 准确地：https://community.myfitnesspal.com/en/discussion/10703170/what-were-eating/p1）提取用户信息，特别是用户名、消息和发布日期，并将它们加载到 csv 上的列中。到目前为止，我有这段代码，但不确定如何继续：

from bs4 import BeautifulSoup
import csv
import requests

# get page source and create a BS object
print('Reading page...')

page= requests.get('https://community.myfitnesspal.com/en/discussion/10703170/what-were-eating/p1')
src = page.content

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

#container = soup.select('#vanilla_discussion_index > div.container')

container = soup.select('#vanilla_discussion_index > div.container > div.row > div.content.column > div.CommentsWrap > div.DataBox.DataBox-Comments > ul')

postdata = soup.select('div.Message')

user = []
date = []
text = []

for post in postdata:
    text.append(BeautifulSoup(str(post), 'html.parser').get_text().encode('utf-8').strip())

print(text) # this stores the text of each comment/post in a list,
            # so next I'd want to store this in a csv with columns 
            # user, date posted, post with this under the post column
            # and do the same for user and date

Answer 1

此脚本将从页面获取所有消息并将它们保存在 data.csv:

import csv
import requests
from bs4 import BeautifulSoup


url = 'https://community.myfitnesspal.com/en/discussion/10703170/what-were-eating/p1'

soup = BeautifulSoup(requests.get(url).content, 'html.parser')

all_data = []
for u, d, m in zip(soup.select('.Username'), soup.select('.DateCreated'), soup.select('.Message')):
    all_data.append([u.text, d.get_text(strip=True),m.get_text(strip=True, separator='\n')])

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

来自 LibreOffice 的屏幕截图：

Answer 2

我在网络抓取方面喜欢遵循的一条经验法则是尽可能具体，不要收集不必要的信息。因此，例如，如果我想 select 一个用户名，我检查包含我需要的信息的元素：

<a class="Username" href="...">Username</a>

由于我正在尝试收集用户名，因此 select 通过 class“用户名”:

最有意义

soup.select("a.Username")

这给了我在页面上找到的所有用户名的列表，这很好，但是，如果我们想要 select“包”中的数据（通过 post您的示例我们需要单独收集每个 post。

要完成此操作，您可以执行以下操作：

comments = soup.select("div.comment")

这样可以更轻松地执行以下操作：

with open('file.csv', 'w', newline='') as file:
    writer = csv.writer(file)
    writer.writerow(['user', 'date', 'text']
    for comment in comments:
        username = comment.select_one("div.Username")
        date = comment.select_one("span.BodyDate")
        message = comment.select_one("div.Message")
        writer.writerow([username, date, message])

这样做还可以确保您的数据保持有序，即使某个元素丢失也是如此。

Answer 3

给你：

from bs4 import BeautifulSoup
import csv
import requests


page= requests.get('https://community.myfitnesspal.com/en/discussion/10703170/what-were-eating/p1')
soup = BeautifulSoup(page.content, 'html.parser')
container = soup.select('#vanilla_discussion_index > div.container > div.row > div.content.column > div.CommentsWrap > div.DataBox.DataBox-Comments > ul > li')

with open('data.csv', 'w') as f:
    writer = csv.DictWriter(f, fieldnames=['user', 'date', 'text'])
    writer.writeheader()
    for comment in container:
        writer.writerow({
            'user': comment.find('a', {'class': 'Username'}).get_text(),
            'date': comment.find('span', {'class': 'BodyDate DateCreated'}).get_text().strip(),
            'text': comment.find('div', {'class': 'Message'}).get_text().strip()
        })

我如何从讨论区提取用户名、post 和日期 post？

How would I extract username, post, and date posted from discussion board?

python

web-scraping

beautifulsoup

python-requests

data-mining