Find element using if else or try except in Python Selenium

Question

I am confused which is the best and correct way to check if element exists or not? Using try-except or if-else? What would be the difference and what are advantages/disadvantages of both when trying to find element?

def find_logo():
    return driver.find_elements(By.CSS_SELECTOR, ".navbar-brand [src='/logo/logo.svg']")

if find_logo(): 
    print("Found the logo")
else:
    print("Cannot find the logo")

So will get the same result with try except:

def find_logo():
    return driver.find_element(By.CSS_SELECTOR, ".navbar-brand [src='/logo/logo.svg']")

try:
    find_logo()
    print("Found the logo")
except NoSuchElementException:
    print("Cannot find the logo")

Both seem to work the same way but which is the correct way to do it?

Answer 1

Canonically both the if-else and try-except logic needs to be revamped however they needs to be implemented as per your usecase.

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if find_logo(): The if find_logo() will be always successful as in def find_logo() you have used find_elements() which may not return any elements at all. In such case you may require to check if the list size is not 0.

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try: find_logo(): try: find_logo() seems to be better organized in comarision to the other with NoSuchElementException check in place when the specific element isn't found.

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Code optimization

However as per best practices, when looking for an element, you need to induce WebDriverWait for the visibility_of_element_located() and you can use the following logic:

try:
    WebDriverWait(driver, 20).until(EC.visibility_of_element_located((By.CSS_SELECTOR, ".navbar-brand [src='/logo/logo.svg']")))
    print("Found the logo")
except TimeoutException:
    print("Cannot find the logo")
    

Note : You have to add the following imports :

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

Answer 2

In first case function return a list and in the second case, function return that web element that you are looking for.