Develop Reference

How can I check if an element exists on a page using Selenium XPath?

I'm writing a script in to do some webscraping on my Firebase for a few select users. After accessing the events page for a user, I want to check for the condition that no events have been logged by that user first.
For this, I am using Selenium and Python. Using XPath seems to work fine for locating links and navigation in all other parts of the script, except for accessing elements in a table. At first, I thought I might have been using the wrong XPath expression, so I copied the path directly from Chrome's inspection window, but still no luck.
As an alternative, I have tried to copy the page source and pass it into Beautiful Soup, and then parse it there to check for the element. No luck there either.
Here's some of the code, and some of the HTML I'm trying to parse. Where am I going wrong?
# Using WebDriver - always triggers an exception
def check_if_user_has_any_data():
try:
time.sleep(10)
element = WebDriverWait(driver, 10).until(EC.presence_of_all_elements_located((By.XPATH, '//*[#id="event-table"]/div/div/div[2]/mobile-table/md-whiteframe/div[1]/ga-no-data-table/div')))
print(type(element))
if element == True:
print("Found empty state by copying XPath expression directly. It is a bit risky, but it seems to have worked")
else:
print("didn’t find empty state")
except:
print("could not find the empty state element", EC)
# Using Beautiful Soup
def check_if_user_has_any_data#2():
time.sleep(10)
html = driver.execute_script("return document.documentElement.outerHTML")
soup = BeautifulSoup(html, 'html.parser')
print(soup.text[:500])
print(len(soup.findAll('div', {"class": "table-row-no-data ng-scope"})))
HTML
<div class="table-row-no-data ng-scope" ng-if="::config" ng-class="{overlay: config.isBuilderOpen()}">
<div class="no-data-content layout-align-center-center layout-row" layout="row" layout-align="center center">
<!-- ... -->
</div>
The first version triggers the exception and is expected to evaluate 'element' as True. Actual, the element is not found.
The second version prints the first 500 characters (correctly, as far as I can tell), but it returns '0'. It is expected to return '1' after inspecting the page source.

Use the following code:
elements = driver.find_elements_by_xpath("//*[#id='event-table']/div/div/div[2]/mobile-table/md-whiteframe/div[1]/ga-no-data-table/div")
size = len(elements)
if len(elements) > 0:
# Element is present. Do your action
else:
# Element is not present. Do alternative action
Note: find_elements will not generate or throw any exception

Here is the method that generally I use.
Imports
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.common.by import By
Method
def is_element_present(self, how, what):
try:
self.driver.find_element(by=how, value=what)
except NoSuchElementException as e:
return False
return True

Some things load dynamically. It is better to just set a timeout on a wait exception.

If you're using Python and Selenium, you can use this:
try:
driver.find_element_by_xpath("<Full XPath expression>") # Test the element if exist
# <Other code>
except:
# <Run these if element doesn't exist>

I've solved it. The page had a bunch of different iframe elements, and I didn't know that one had to switch between frames in Selenium to access those elements.
There was nothing wrong with the initial code, or the suggested solutions which also worked fine when I tested them.
Here's the code I used to test it:
# Time for the page to load
time.sleep(20)
# Find all iframes
iframes = driver.find_elements_by_tag_name("iframe")
# From inspecting page source, it looks like the index for the relevant iframe is [0]
x = len(iframes)
print("Found ", x, " iFrames") # Should return 5
driver.switch_to.frame(iframes[0])
print("switched to frame [0]")
if WebDriverWait(driver, 10).until(EC.presence_of_all_elements_located((By.XPATH, '//*[#class="no-data-title ng-binding"]'))):
print("Found it in this frame!")

Check the length of the element you are retrieving with an if statement,
Example:
element = ('https://www.example.com').
if len(element) > 1:
# Do something.

Continue when element is not found in selenium python

The following script follows a page in Instagram:
browser = webdriver.Chrome('./chromedriver')
# GO INSTAGRAM PAGE FOR LOGIN
browser.get('https://www.instagram.com/accounts/login/?hl=it')
sleep(2)
# ID AND PASSWORD
elem = browser.find_element_by_name("username").send_keys('test')
elem = browser.find_element_by_name("password").send_keys('passw')
# CLICK BUTTON AND OPEN INSTAGRAM
sleep(5)
good_elem = browser.find_element_by_xpath('//*[#id="react-root"]/section/main/div/article/div/div[1]/div/form/span/button').click()
sleep(5)
browser.get("https://www.instagram.com")
# GO TO PAGE FOR FOLLOW
browser.get("https://www.instagram.com/iam.ai4/")
sleep(28)
segui = browser.find_element_by_class_name('BY3EC').click()
If an element with class BY3EC isn't found I want the script to keep working.

When an element is not found it throws NoSuchElementException, so you can use try/except to avoid that, for example:
from selenium.common.exceptions import NoSuchElementException
try:
segui = browser.find_element_by_class_name('BY3EC').click()
except NoSuchElementException:
print('Element BY3EC not found') # or do something else here
You can take a look at selenium exceptions to get an idea of what each one of them is for.

surround it with try catches, than you can build a happy path and handle failures as well, so your test case will always work

Best practice is to not use Exceptions to control flow. Exceptions should be exceptional... rare and unexpected. The simple way to do this is to get a collection using the locator and then see if the collection is empty. If it is, you know the element doesn't exist.
In the example below we search the page for the element you wanted and check to see that the collection contains an element, if it does... click it.
segui = browser.find_elements_by_class_name('BY3EC')
if segui:
segui[0].click()

Loop through find_element_by_name python selenium

I have a code where it looks for a name and I am trying to write an if statement that says if it can't find that name look for something else.
What I have so far is as follows:
excel = driver.find_element_by_name("Export to Excel")
if excel == None:
driver.implicitly_wait(15)
search = driver.find_element_by_xpath("//span[#id='inplaceSearchDiv_WPQ2_lsimgspan']")
search.click()
else:
excel.click()
I know what's inside the if statement works because I tested it out. Am I suppoed to change my argument in my if statement? The error I get is selenium.common.exceptions.NoSuchElementException: Message: No such element I tried entering "No such element" instead of "None" but I still get the same error. Also it tells me Exception Unhandled NoSuchElementException('No such element', None, None) can some give me advise on what I am doing wrong with the if statement? The error also say that it is found at excel = driver.find_element_by_name("Export to Excel") when the button isn't present in the page. When it is, it'll go straight to the else part of the statement

The find_element_by_name method on your driver will raise the NoSuchElementException exception if it cannot find the webelement.
Try this
from selenium.common.exceptions import NoSuchElementException
try:
excel = driver.find_element_by_name("Export to Excel")
excel.click()
except NoSuchElementException:
driver.implicitly_wait(15)
search = driver.find_element_by_xpath("//span[#id='inplaceSearchDiv_WPQ2_lsimgspan']")
search.click()

How to use the try/except with Selenium Webdriver when having Exceptions on Python

I'm trying the use a try/except statement to findout if an element exists in the WebDrive or not, if so then run a specific code line,
try:
WebDriver.find_element_by_css_selector('div[class="..."')
except NoSuchElement:
ActionToRunInCaseNoSuchElementTrue
else:
ActionToRunInCaseNoSuchElementFalse
but running this code gives an error:
NameError: name 'NoSuchElement' is not defined
how should the Exception be defined?
Is there any shorter/easier way to check if an element does exist in a web page and run a command if so and another if not?

To be able to use required exception you have to import it first with correct name (NoSuchElement -> NoSuchElementException):
from selenium.common.exceptions import NoSuchElementException
try:
WebDriver.find_element_by_css_selector('div[class="..."')
except NoSuchElementException:
ActionToRunInCaseNoSuchElementTrue

Instead of using try except you can use find_elements and check if the returned list has any elements
elements = WebDriver.find_elements_by_css_selector('div[class="..."')
if not elements:
ActionToRunInCaseNoSuchElementTrue
else:
ActionToRunInCaseNoSuchElementFalse
# the element is in elements[0]

How can I ignore the exception in Selenium?

I use Python Selenium for scraping a website,
but my crawler stopped because of a exception:
StaleElementReferenceException: Message: stale element reference: element is not attached to the page document
How can i continue to crawl even if the element is not attached?
UPDATE
i change my code to:
try:
libelle1 = prod.find_element_by_css_selector('.em11')
libelle1produit = libelle1.text # libelle1 OK
libelle1produit = libelle1produit.decode('utf-8', 'strict')
except StaleElementReferenceException:
pass
but i have this exception
NoSuchElementException: Message: no such element
i also tried this one:
try:
libelle1 = prod.find_element_by_css_selector('.em11')
libelle1produit = libelle1.text # libelle1 OK
libelle1produit = libelle1produit.decode('utf-8', 'strict')
except :
pass

Put a try-except block around the piece of code that produced that error.

To be more specific about what John Gordon is talking about. Handle the StaleElementReferenceException common selenium exception and ignore it:
from selenium.common.exceptions import StaleElementReferenceException
try:
element.click()
except StaleElementReferenceException: # ignore this error
pass # TODO: consider logging the exception

It looks like the browser rendering engine or Javascript engine is using the element and it is blocking other external operations on this element. You can attempt to access it after some time. If it is not accessible for longer duration, an exception can be thrown. Some good examples are given here.