Python 如何使用if-elif-else检查元素是否存在

我有一个下拉菜单，我需要检查它的条目。如果没有条目，我可以添加新条目，如果只有一个条目，我将其删除并添加新条目，当我有多个条目（>=2）时，我无法继续添加条目。我可以通过

person\u rem\u btn

进行检查。如果我只有一个按钮

doc\u person\u table:0:person\u rem\u btn

我可以继续，如果我有第二个按钮

doc\u person\u table:1:person\u rem\u btn

我无法继续

我得到一个例外：

selenium.common.exceptions.NoSuchElementException: Message: no such element: Unable to locate element: {"method":"xpath","selector":"//*[@id='frmMain:doc_person_table:1:person_rem_btn']/span[1]"}

然而，这就是重点，这个元素可能不可用，我只是检查它的存在。我将感谢任何帮助。这是我的密码：

if driver.find_element_by_xpath("//*[@id='frmMain:doc_person_table:1:person_rem_btn']/span[1]") == True:
   print ("there are already many entries")
   driver.close()
elif (driver.find_element_by_xpath("//*[@id='frmMain:doc_person_table:1:person_rem_btn']/span[1]") == False and driver.find_element_by_xpath("//*[@id='frmMain:doc_person_table:0:person_rem_btn']/span[1]") == True):
   print ("there is only one entry, it will be removed to proceed")
   WebDriverWait(driver, 10).until(EC.element_to_be_clickable((By.XPATH, "//*[@id='frmMain:doc_person_table:0:person_rem_btn']/ span[1]"))).click()
else:
    print ("there is no entry, you can proceed")

---

find_element\u by_xpath

不返回

True

或

False

，它返回

WebElement

或抛出

NoSuchElementException

。您可以使用

find_elements\u by_xpath

获取列表并检查此列表是否包含任何元素。从等待一个不相关的元素开始，该元素可以指示页面已加载

WebDriverWait(driver, 10).until(EC.visibility_of_element_located((By.XPATH, "//*[@id^='frmMain:doc_person_table")))
# assuming this element will always appear when the page is loaded

elements = driver.find_elements_by_xpath("//*[@id='frmMain:doc_person_table:1:person_rem_btn']/span[1]")
if elements: # more verbose if len(elements) > 0
    print ("there are already many entries")
    driver.close()
else:
    elements = driver.find_elements_by_xpath("//*[@id='frmMain:doc_person_table:0:person_rem_btn']/span[1]")
    if elements:
        print ("there is only one entry, it will be removed to proceed")
        elements[0].click()
    else:
        print ("there is no entry, you can proceed")

---

您可以采用几种方法，其中一种方法是创建一个下拉项列表，用于显示所有元素的可见性（），并探测列表大小：

• 使用

  CSS\u选择器

  ：

  list = WebDriverWait(driver, 20).until(EC.visibility_of_all_elements_located((By.CSS_SELECTOR, "[id*='doc_person_table'][id$='person_rem_btn']>span")))
  if not list:
      print ("there is no entry, you can proceed")
      # other steps
  elif len(list) == 1
      print ("there is only one entry, it will be removed to proceed")
      # other steps
  else:
      print ("there are already many entries")
      break
  

  list = WebDriverWait(driver, 20).until(EC.visibility_of_all_elements_located((By.XPATH, "//*[contains(@id, 'doc_person_table') and contains(@id, 'person_rem_btn')]/span")))
  if not list:
      print ("there is no entry, you can proceed")
      # other steps
  elif len(list) == 1
      print ("there is only one entry, it will be removed to proceed")
      # other steps
  else:
      print ("there are already many entries")
      break
  

• 使用

  XPATH

  ：

  list = WebDriverWait(driver, 20).until(EC.visibility_of_all_elements_located((By.CSS_SELECTOR, "[id*='doc_person_table'][id$='person_rem_btn']>span")))
  if not list:
      print ("there is no entry, you can proceed")
      # other steps
  elif len(list) == 1
      print ("there is only one entry, it will be removed to proceed")
      # other steps
  else:
      print ("there are already many entries")
      break
  

  list = WebDriverWait(driver, 20).until(EC.visibility_of_all_elements_located((By.XPATH, "//*[contains(@id, 'doc_person_table') and contains(@id, 'person_rem_btn')]/span")))
  if not list:
      print ("there is no entry, you can proceed")
      # other steps
  elif len(list) == 1
      print ("there is only one entry, it will be removed to proceed")
      # other steps
  else:
      print ("there are already many entries")
      break
  

---

@jitlp应该是

find_elements\u by_xpath

，请参阅更新的答案。@jitlp您可以为不相关的元素添加

WebDriverWait

，您知道这些元素将始终存在，并指示页面已加载。请参阅更新的答案。@jitlp此元素只是一个示例，您可以选择任何其他元素。它只是用来表示页面已加载。我不熟悉这个网站，所以我根据问题中的定位器发布了。@jitlp您是指

elements=driver中的元素。通过xpath（“/*[@id='frmMain:doc\u person\u table:0:person\u rem\u btn']/span[1]”和
元素[0]查找元素。单击（）？或者其他与此无关的问题？@jitlp这听起来像是一个新问题，如果没有看到更详细的代码和html，在评论中很难回答，但您应该记住，移动到另一个页面或刷新页面（
click（）
有时会导致页面刷新）使以前定位的所有图元无效，您需要重新定位它们。