python - 为什么在 Selenium 中等待元素加载后元素仍未出现？

Question

我有一个我想抓取的特定 URL，但是，某个元素在页面完全加载之前不会加载，我无法让 Selenium 找到它:

from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait

driver = webdriver.Chrome(Insert Driver Path Here)
game_url = "https://rbsdm.com/stats/box_scores/?_inputs_&type=%22reg%22&away=%22ARI%22&home=%22SF%22&year=2020"
driver.get(game_url)
element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.CLASS_NAME, "table table-striped table-hover table-responsive"))
    )
print(element)

<div>有我想要的表的 ID qbs ，然而，它显然在初始加载时不包含任何内容。该表具有我在制作 element 时使用的类名变量。

页面的数据肯定是在我给它的 10 秒窗口后加载的，所以我很困惑这不起作用。

Answer 1

在您的代码中，当您搜索所需的 HTML 元素时:

element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.CLASS_NAME, "table table-striped table-hover table-responsive"))
    )

您正在寻找一个类名，但是table table-striped table-hover table-responsive 不是一个类名，它是一个 CSS 选择器(带链接带点的空格 .):

table.table-striped.table-hover.table-responsive

所以，要么使用上面的 CSS 选择器(注意 By.CSS_SELECTOR):

element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.CSS_SELECTOR, "table.table-striped.table-hover.table-responsive"))
    )

或者使用类名:

element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.CLASS_NAME, "table"))
    )

---

这是一个完整的工作示例:

from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait


driver = webdriver.Chrome()
game_url = "https://rbsdm.com/stats/box_scores/?_inputs_&type=%22reg%22&away=%22ARI%22&home=%22SF%22&year=2020"
driver.get(game_url)
element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.CLASS_NAME, "table"))
    )
print(element.text)

输出:

Player Plays EPA/play Total EPA aDoT CMP% xCMP% CPOE xQBR
K.Murray 54 0.18 9.9 5.2 70.3 72.5 -2.2 63.6
J.Garoppolo 38 0.1 3.6 7 59.4 65.6 -6.2 54.9