关于python list 写进txt中的问题

Question

各位大神好，我爬取腾讯新闻的新闻标题加入到一个列表当中，在用file.write()写进 新闻.txt的时候，为啥老是写入列表的最后一个呢？？

from bs4 import BeautifulSoup
import requests
url = 'http://news.qq.com/'
wb_data = requests.get(url).text
soup = BeautifulSoup(wb_data,'lxml')
news_titles = soup.select('p.text > em.f14 > a.linkto')
for n in news_titles:
    title = n.get_text()

    link = n.get("href")


    file = open('/Users/sufan/Desktop/新闻.txt', 'w')
    b = []
    b.append(title + '链接' + link)
    file.write(str(b))
    

这个是我爬取出来的东西（print（b）的结果）

这个是写入txt中的内容

Answer 1

File operations are placed in a loop? In this way, every operation, every file opening, every write is overwritten...

# -*- coding: utf-8 -*-
import sys

reload(sys)
sys.setdefaultencoding('utf-8')

from bs4 import BeautifulSoup
import requests
url = 'http://news.qq.com/'
wb_data = requests.get(url).text
soup = BeautifulSoup(wb_data,'lxml')
news_titles = soup.select('p.text > em.f14 > a.linkto')
file = open('新闻.txt', 'a')
for n in news_titles:
    title = n.get_text()

    link = n.get("href")
    b = str(title) + ' 链接: ' + link +"\n"
    file.write(str(b))

file.close()

Answer 2

for n in news_titles:
    title = n.get_text()

    link = n.get("href")


    b = []
    b.append(title + '链接' + link)
    
with open('/Users/sufan/Desktop/新闻.txt', 'w') as file:
    file.write(str(b))

Answer 3

The action I wrote is in the wrong place