首先，EOL 代表“行尾”，如果 python 不喜欢您定义字符串的方式或使用了一些不可靠的字符，您通常会收到此错误。为避免这种情况，您可以在原始代码中对字符串进行三重引用，如下所示：
stock_history = '''<div class="buy-now-bar-con">
<a class="current" href="antminer_s9_asic_bitcoin_miner.htm?
flag=overview">Overview</a>
<a href="antminer_s9_asic_bitcoin_miner.htm?
flag=specifications">Specification</a>
<a href="antminer_s9_asic_bitcoin_miner.htm?flag=gallery">Gallery</a>
<a class="btn-buy-now" href="javascript:;" style="background:#a7a4a4;
cursor:not-allowed;" target="_self" title="sold out!">Coming soon</a>
</div>'''
这很难看，所以我去掉了那个大字符串，因为它没有必要。您应该想从stock 变量中获取的唯一信息是产品是否售罄。为此，您可以将bs4.element.Tag 转换为str 类型并使用正则表达式检查是否存在“已售罄！”子串。无论您在进行抓取、处理文本数据或执行任何形式的 XML 或 HTML 解析，正则表达式确实派上用场，因此我鼓励您阅读它们。
更多信息：https://www.regular-expressions.info/
您可以在这里轻松测试 python 正则表达式捕获：https://pythex.org/
这是修改后的代码，它可以完成您试图让它做的事情。
import re
import csv
import requests
from datetime import datetime
from bs4 import BeautifulSoup
def stock_check(url):
"""Function checks url for 'sold out!' substring in url.content"""
soup = BeautifulSoup(url.content, "lxml") #Need to use lxml parser
stock = soup.find("div", "buy-now-bar-con") #Check the html tags for sold out/coming soon info.
stock_status = re.findall(r"(sold out!)", str(stock)) #Returns list of captured substring if exists.
return stock_status[0] # returns "sold out!" from soup string.
now = datetime.now()
url = requests.get('https://shop.bitmain.com/antminer_s9_asic_bitcoin_miner.htm')
if stock_check(url) == "sold out!":
print(str(now) + ": Still not in stock...")
else:
print(str(now) + ": Now in stock!")
试试看，如果您有任何问题，请告诉我！
编辑：OP 询问如何定期检查网页并包含电子邮件通知。需要对原始解决方案进行一些更改，例如在requests headers 字段中设置userAgent 信息。还为BeautifulSoup 对象切换到html.parser 而不是lxml，以正确处理url.content 中的javascript。
import re
import time
import smtplib
import requests
from datetime import datetime
from bs4 import BeautifulSoup
def stock_check(url):
"""Checks url for 'sold out!' substring in buy-now-bar-con"""
soup = BeautifulSoup(url.content, "html.parser") #Need to use lxml parser
stock = soup.find("div", "buy-now-bar-con") #Check the html tags for sold out/coming soon info.
stock_status = re.findall(r"sold out!", str(stock)) #Returns list of captured substring if exists.
return stock_status # returns "sold out!" from soup string.
def send_email(address, password, message):
"""Send an e-mail to yourself!"""
server = smtplib.SMTP("smtp.gmail.com", 587) #e-mail server
server.ehlo()
server.starttls()
server.login(address,password) #login
message = str(message) #message to email yourself
server.sendmail(address,address,message) #send the email through dedicated server
return
def stock_check_listener(url, address, password, run_hours):
"""Periodically checks stock information."""
listen = True # listen boolean
start = datetime.now() # start time
while(listen): #while listen = True, run loop
if "sold out!" in stock_check(url): #check page
now = datetime.now()
print(str(now) + ": Not in stock.")
else:
message = str(now) + ": NOW IN STOCK!"
print(message)
send_email(address, password, message)
listen = False
duration = (now - start)
seconds = duration.total_seconds()
hours = int(seconds/3600)
if hours >= run_hours: #check run time
print("Finished.")
listen = False
time.sleep(30*60) #Wait N minutes to check again.
return
if __name__=="__main__":
#Set url and userAgent header for javascript issues.
page = "https://shop.bitmain.com/antminer_s9_asic_bitcoin_miner.htm"
headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36',
'Content-Type': 'text/html'}
#URL request.
url = requests.get(url=page,
headers=headers)
#Run listener to stream stock checks.
address = "user@gmail.com" #your email
password = "user.password" #your email password
stock_check_listener(url=url,
address=address,
password=password,
run_hours=1)
现在，程序将启动一个while 循环，该循环会定期从网页请求信息。您可以通过更改run_hours 变量来设置超时（以小时为单位）。您还可以通过在stock_check_listener 中更改N 来设置睡眠/等待时间（以分钟为单位）。在这种情况下，我使用了gmail，如果您在给自己发送电子邮件时收到错误消息，那么您需要点击此链接：https://myaccount.google.com/lesssecureapps，并允许不太安全的应用程序（您的 python 程序）访问您的 gmail 帐户。