python - 如何使用 Selenium 和 Python 处理 try 循环中的错误

Question

我想使用 selenium 进行搜索，然后在 DDG 搜索结束时单击“更多结果”按钮。
DDG 搜索在显示查询的所有结果时不再显示该按钮。
在没有按钮的情况下，我想退出 try 循环。
我将分享我现在正在尝试的内容。我之前也尝试过这两个选项:If len(button_element) > 0: button_element.click()我试过If button_element is not None: button_element.click() .
我想要使​​用 Selenium 的解决方案，以便它显示浏览器，因为它有助于调试
这是我的代码，带有可重现的示例:

    from selenium import webdriver
    from selenium.webdriver.common.keys import Keys
    from selenium.webdriver.chrome.options import Options
    from bs4 import BeautifulSoup

    browser = webdriver.Chrome()        
    browser.get("https://duckduckgo.com/")
    search = browser.find_element_by_name('q')
    search.send_keys("this is a search" + Keys.RETURN)
    html = browser.page_source

    try:
        button_element = browser.find_element_by_class_name('result--more__btn')

        try:
            button_element.click()
        except SystemExit:
            print("No more pages")

    except:
        pass

Answer 1

单击 duckduckgo 末尾的更多结果按钮使用 Selenium 搜索结果WebDriver你要诱导WebDriverWait对于element_to_be_clickable()您可以使用以下任一Locator Strategies :

代码块:

from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.keys import Keys
from selenium.common.exceptions import TimeoutException

options = webdriver.ChromeOptions() 
options.add_argument("start-maximized")
options.add_experimental_option("excludeSwitches", ["enable-automation"])
options.add_experimental_option('useAutomationExtension', False)
driver = webdriver.Chrome(options=options, executable_path=r'C:\WebDrivers\chromedriver.exe')
driver.get('https://duckduckgo.com/')
WebDriverWait(driver, 20).until(EC.element_to_be_clickable((By.NAME, "q"))).send_keys("this is a search" + Keys.RETURN)
while True:
      try:
          WebDriverWait(driver, 20).until(EC.element_to_be_clickable((By.CSS_SELECTOR, "a.result--more__btn"))).click()
          print("Clicked on More Results button")
      except TimeoutException:
          print("No more More Results button")
          break
driver.quit()

控制台输出:

Clicked on More Results button
Clicked on More Results button
Clicked on More Results button
Clicked on More Results button
Clicked on More Results button
No more More Results button

You can find a relevant discussion in How to extract the text from the search results of duckduckgo using Selenium Python