Python 代码写入 csv 文件，只打印两个文本条目

Question

#Stuff needed to run
import requests
import urllib.request
import io
from bs4 import BeautifulSoup as soup

#Pick url, request it, save response, read response, soup it into variable
my_url = 'https://old.reddit.com/r/all/'
request = urllib.request.Request(my_url,headers={'User-Agent': 'your bot 0.1'})
response = urllib.request.urlopen(request)
page_html = response.read()
page_soup = soup(page_html, "html.parser")

#get all the posts, get one post, get all the authors, get one author
posts = page_soup.findAll("div", {"class": "top-matter"})
post = posts[0]
authors = page_soup.findAll("p", {"class":"tagline"})
author = authors[0]

#make filename, open to write, set the headers, write the headers,
filename = "redditAll.csv"
f = open(filename, "w")
headers = "Title of the post, Author of the post\n"
f.write(headers)

#for the post and author in posts and authors, get one of each, open the file & write it, repeat
for post, author in zip(posts, authors):
    post_text = post.p.a.text.replace(",", " -")
    username = author.a.text
    with open(filename, "w", encoding="utf-8") as f:
        f.write(post_text + "," + username + "\n")

#close the file
f.close()

运行此代码并打开 csv 文件后，只有两个单元格中有文本。

应该不止两个，因为 reddit.com/r/all 上的帖子不止两个

改了

for post, author in zip(posts, authors):
    post_text = post.p.a.text.replace(",", " -")
    username = author.a.text
    with open(filename, "w", encoding="utf-8") as f:
        f.write(post_text + "," + username + "\n")

到这里

with open(filename, "w", encoding="utf-8") as f:
    for post, author in zip(posts, authors):
        post_text = post.p.a.text.replace(",", " -")
        username = author.a.text
        f.write(post_text + "," + username + "\n")

Answer 1

试试这个：

# for the post and author in posts and authors, get one of each, open the file & write it, repeat
def writer():
    with open(filename, "w", encoding="utf-8") as f:
        for post_, author_ in zip(posts, authors):
            post_text = post_.p.a.text.replace(",", " -")
            username = author_.a.text
            # with open(filename, "w", encoding="utf-8") as f:
            f.write(post_text + "," + username + "\n")

writer()

Answer 2

您可以使用a 参数以附加模式打开文件，第二次打开文件写入时，请查看SO thread 以了解如何执行此操作。或者将with open(filename, "w", encoding="utf-8") as f:移到循环外

w 参数将覆盖文件中的先前数据，因此每次循环运行时，记录将被新记录覆盖，只留下文件中的最终记录

作为 cmets 提到的内容之一，我还将使用内置的 csv 库来读取/写入 csv 文件。 Here 是它的文档

Answer 3

改了

for post, author in zip(posts, authors):
    post_text = post.p.a.text.replace(",", " -")
    username = author.a.text
    with open(filename, "w", encoding="utf-8") as f:
        f.write(post_text + "," + username + "\n")

到这里

with open(filename, "w", encoding="utf-8") as f:
    for post, author in zip(posts, authors):
        post_text = post.p.a.text.replace(",", " -")
        username = author.a.text
        f.write(post_text + "," + username + "\n")