Python/Selenium, xpath 突然停止工作

Question

我有一个脚本可以从 coinmarketcap 上的加密货币列表中提取名称。要获取我使用函数的名称：

num = 0
def print_name():
    global num
    num = num + 1
    if num == 100:
         exit()
    sleep(0.1)
    names = driver.find_element(By.XPATH, '/html/body/div[1]/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr['+str(num)+']/td[3]/div/a/div/div/div/p')
    print(names.text)

要遍历列表，我必须更改 xpath 中的一个数字，即 +str(num)+，这样 xpath 每次都会移动到列表中的下一个名称，但在编号 18 处，脚本只是randomlly 停止工作并给出错误：

Message: no such element: Unable to locate element:

即使 xpath 保持不变，我检查了多次，使驱动程序刷新，甚至向下滚动以加载数据，但程序无法识别路径。

不是因为网站屏蔽了自动化，我尝试从数字5开始，所以在达到数字18之前请求较少，但仍然没有用。

这是错误消息：

Traceback (most recent call last):
  File "C:\Users\fkahd\PycharmProjects\coingecko api\sandbox.py", line 27, in <module>
    print_name()
  File "C:\Users\fkahd\PycharmProjects\coingecko api\sandbox.py", line 23, in print_name
    names = driver.find_element(By.XPATH, '/html/body/div[1]/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr['+str(num)+']/td[3]/div/a/div/div/div/p')
  File "C:\Users\fkahd\PycharmProjects\coingecko api\venv\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 1244, in find_element
    return self.execute(Command.FIND_ELEMENT, {
  File "C:\Users\fkahd\PycharmProjects\coingecko api\venv\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 424, in execute
    self.error_handler.check_response(response)
  File "C:\Users\fkahd\PycharmProjects\coingecko api\venv\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 247, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.NoSuchElementException: Message: no such element: Unable to locate element: {"method":"xpath","selector":"/html/body/div[1]/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr[18]/td[3]/div/a/div/div/p"}
  (Session info: chrome=98.0.4758.82)
Stacktrace:
Backtrace:
    Ordinal0 [0x00557AC3+2587331]
    Ordinal0 [0x004EADD1+2141649]
    Ordinal0 [0x003E3BB8+1063864]
    Ordinal0 [0x004101CE+1245646]
    Ordinal0 [0x004103CB+1246155]
    Ordinal0 [0x0043A612+1418770]
    Ordinal0 [0x004286D4+1345236]
    Ordinal0 [0x00438A0A+1411594]
    Ordinal0 [0x004284A6+1344678]
    Ordinal0 [0x004053F6+1201142]
    Ordinal0 [0x004062E6+1204966]
    GetHandleVerifier [0x006FDF22+1680738]
    GetHandleVerifier [0x007B0DBC+2413564]
    GetHandleVerifier [0x005ED151+563089]
    GetHandleVerifier [0x005EBF13+558419]
    Ordinal0 [0x004F081E+2164766]
    Ordinal0 [0x004F5508+2184456]
    Ordinal0 [0x004F5650+2184784]
    Ordinal0 [0x004FF5BC+2225596]
    BaseThreadInitThunk [0x764AFA29+25]
    RtlGetAppContainerNamedObjectPath [0x77BB7A9E+286]
    RtlGetAppContainerNamedObjectPath [0x77BB7A6E+238]

它说：无法定位元素：{"method":"xpath","selector":"/html/body/div[1]/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr[18]/td[3]/div/a/div/div/div/p"}

但是，当我去检查元素时，路径是

/html/body/div/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr[18]/td[3]/div/a/div/div/div/p

与错误消息中的完全相同。

Html 的文字： <p color="text3" class="sc-1eb5slv-0 gGIpIK coin-item-symbol" font-size="1">SCRT</p>

完整代码：

from selenium import webdriver
from selenium.webdriver.common.by import By
from time import sleep

driver = webdriver.Chrome("C:\Program Files (x86)\chromedriver.exe")
driver.get("https://coinmarketcap.com/view/defi/")
sleep(2)
driver.refresh()

num = 0
num2 = 17

def loop2():
    global num2
    global names2
    num2 = num2 + 1
    if num2 == 100:
        exit()
    sleep(0.1)
    names2 = driver.find_element(By.XPATH, '/html/body/div/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr['+str(num2)+']/td[3]/div/a/div/div/div/p')

def print_name():
    global num
    num = num + 1
    if num == 18:
         loop2()
    sleep(0.1)
    names = driver.find_element(By.XPATH, '/html/body/div[1]/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr['+str(num)+']/td[3]/div/a/div/div/div/p')
    print(names.text)

while True:
    print_name()

快速更新这里是 xpath 17 和 18 的示例，但是 18 不起作用：

/html/body/div/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr[18]/td[3]/div/a/div/div/div/p

/html/body/div/div/div[1]/div[2]/div/div[1]/div[2]/table/tbody/tr[17]/td[3]/div/a/div/div/div/p

感谢您的帮助，祝您愉快。

Answer 1

从 Coinmarketcap you have to induce WebDriverWait for visibility_of_all_elements_located() and you can use either of the following 内市值排名靠前的 DeFi 代币中提取名称：

使用CSS_SELECTOR:

driver.get("https://coinmarketcap.com/view/defi/")
print([my_elem.text for my_elem in WebDriverWait(driver, 20).until(EC.visibility_of_all_elements_located((By.CSS_SELECTOR, "p[class$='coin-item-symbol']")))])

使用 XPATH:

driver.get("https://coinmarketcap.com/view/defi/")
print([my_elem.text for my_elem in WebDriverWait(driver, 20).until(EC.visibility_of_all_elements_located((By.XPATH, "//p[contains(@class, 'coin-item-symbol')]")))])

注意：您必须添加以下导入：

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

Python/Selenium, xpath 突然停止工作

Python/Selenium, xpath suddenly stops working

html

python

error-handling

selenium

xpath