如何尝试使用Selenium查找元素时引发的TypeError？

Question

我正在尝试从网页上抓取所有链接。我正在使用Selenium WebDriver滚动并单击网页中存在的“加载更多”按钮。我正在尝试的代码如下所示：

from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait
from selenium.common.exceptions import ElementNotVisibleException
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import NoSuchElementException
from bs4 import BeautifulSoup

def fetch_links(url):
    chrome_path = r"D:\nishant_pc_d_drive\nishant_pc\d_drive\update_engine\myntra_update\chromedriver.exe"
    driver = webdriver.Chrome(chrome_path)
    driver.get(url)

    while True:
        try:
            scrollcount=1
            while scrollcount<5:
                driver.execute_script("window.scrollTo(0, document.body.scrollHeight);")
                WebDriverWait(driver, 5)
                scrollcount+=1

            WebDriverWait(driver, 10).until(EC.presence_of_element_located(driver.find_elements_by_css_selector('.load_more .sbt-button, .load_more_order .sbt-button')))
            driver.find_element_by_id("loadmore").click()
        except (ElementNotVisibleException,NoSuchElementException) as e:
            print "done"

    x = driver.page_source
    soup2 = BeautifulSoup(x, 'html.parser')
    linkcount=0
    for each in soup2.find_all('a',attrs={"class":"thumb searchUrlClass"}):
        print "https://www.shoppersstop.com/"+each.get('href')
        linkcount+=1
    print linkcount

# thumb searchUrlClass

fetch_links("https://www.shoppersstop.com/women-westernwear-tops-tees/c-A206020")

但不幸的是，它给了我一个错误，如下所示：

Traceback (most recent call last):
  File "D:/INVENTORY/shopperstop/fetch_link.py", line 36, in <module>
    fetch_links("https://www.shoppersstop.com/women-westernwear-tops-tees/c-A206020")
  File "D:/INVENTORY/shopperstop/fetch_link.py", line 21, in fetch_links
    WebDriverWait(driver, 10).until(EC.presence_of_element_located(driver.find_element_by_class_name('sbt-button')))
  File "C:\Python27\lib\site-packages\selenium\webdriver\support\wait.py", line 71, in until
    value = method(self._driver)
  File "C:\Python27\lib\site-packages\selenium\webdriver\support\expected_conditions.py", line 63, in __call__
    return _find_element(driver, self.locator)
  File "C:\Python27\lib\site-packages\selenium\webdriver\support\expected_conditions.py", line 328, in _find_element
    return driver.find_element(*by)
TypeError: find_element() argument after * must be an iterable, not WebElement 

如何解决此错误？谢谢！

Answer 1

错误文本确实令人困惑。

基本上，某些EC（预期条件）方法使用locators，而另一些使用elements。您使用的一个仅接受locator，但您提供了一个element。

所不同的是没有在解释硒教程，但它的排序中的硒API文档解释在这里：

element is WebElement object.
locator is a tuple of (by, path).

这是一个实际的例子locator：

(By.ID, 'someid')

因此，给定初始（错误）代码：

WebDriverWait(driver, 10).until(
    EC.presence_of_element_located(driver.find_element_by_class_name('sbt-button'))
)

...应更新为：

WebDriverWait(driver, 10).until(
    EC.presence_of_element_located((By.CLASS_NAME, 'sbt-button'))
)

注意双括号。那是一个元组被传递给EC方法。

注意：在您的情况下，看起来还需要多个元素，因此还需要使用EC.presence_of_all_elements_located()而不是EC.presence_of_element_located()。

Answer 2

from selenium.webdriver.common.by import By

element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.ID, "myDynamicElement"))
    )