如何使用 if - elif - else 檢查元素是否存在

Question

我有一個下拉菜單，我需要檢查它的條目。 如果沒有條目，我可以添加新條目，如果只有一個條目，我將其刪除並添加新條目，當我有很多條目（> = 2）時，我無法繼續添加條目。 我可以通過person_rem_btn檢查它。 如果我只有一個按鈕doc_person_table:0:person_rem_btn我可以繼續 如果我有第二個按鈕doc_person_table:1:person_rem_btn我無法繼續。

我得到這個例外：

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，這就是重點，這個元素可能不可用，我只是檢查它是否存在。 我將不勝感激任何幫助。 這是我的代碼：

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")

Answer 1

find_element_by_xpath不返回True或False ，它返回WebElement或拋出NoSuchElementException 。 您可以使用find_elements_by_xpath獲取列表並檢查該列表是否包含任何元素。 從等待可以指示頁面已加載的不相關元素開始

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")

Answer 2

您可以采用多種方法，其中一種方法是創建下拉條目列表，為visibility_of_all_elements_located()引入WebDriverWait並探測列表大小：

• 使用CSS_SELECTOR ：

   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

• 使用XPATH ：

   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