尽管网站有不同的结果，但在每个循环中使用 urllib 和 bs4 从地址获得相同的结果

Question

from urllib import request
from bs4 import BeautifulSoup
import time

while True:
    url = "https://coinmarketcap.com/currencies/bitcoin/markets/"

    response = request.urlopen(url)

    soup = BeautifulSoup(response, 'html.parser')
  
    result = (soup.body.div.div.find("div", {"class":"container cmc-main-section"})
        .find("div", {"class":"cmc-main-section__content"}).div.div.div
        .find("div", {"class":"f6l7tu-0 jGlJVl cmc-details-panel-price"}).span.span)
    b=[]
    b = list(filter(None, result))
    print(b[0])

time.sleep(10)

这是我的代码每当我运行程序没有错误但每次它打印相同的值

Answer 1

一开始：它有点咄咄逼人；）你应该在循环中缩进你的 time.sleep(10)。

这是怎么回事？

在您请求网站的那一刻，您会得到一个初始内容，其中还包括 price.

的“chached”值

稍后网站会动态更新内容，因此您必须等待该更新。

你可以做的是使用硒：

from selenium import webdriver
from bs4 import BeautifulSoup
from time import sleep

url = "https://coinmarketcap.com/currencies/bitcoin/markets/"

driver = webdriver.Chrome(executable_path=r'C:\Program Files\ChromeDriver\chromedriver.exe')
while True:
    driver.get(url)
    #driver.implicitly_wait(10) 
    sleep(10)
    soup = BeautifulSoup(driver.page_source,"lxml")

    result = soup.find("div", {"class":"f6l7tu-0 jGlJVl cmc-details-panel-price"}).span.span.text
    print(result)

driver.close()

输出

.391,31
.396,88
.392,99
.381,44
.373,13
.373,13
.359,99
.359,99
.355,07
.327,24
.330,22
.375,47
.341,14
.390,14
.345,10

尽管网站有不同的结果，但在每个循环中使用 urllib 和 bs4 从地址获得相同的结果

getting same result in every loop with urllib and bs4 from an address although site has different results

python

urllib

beautifulsoup

web-scraping

python-3.x