Python Selenium Webdriver - Try except loop

Question

I'm trying to automate processes on a webpage that loads frame by frame. I'm trying to set up a try-except loop which executes only after an element is confirmed present. This is the code I've set up:

from selenium.common.exceptions import NoSuchElementException

while True:
    try:
        link = driver.find_element_by_xpath(linkAddress)
    except NoSuchElementException:
        time.sleep(2)

The above code does not work, while the following naive approach does:

time.sleep(2)
link = driver.find_element_by_xpath(linkAddress)

Is there anything missing in the above try-except loop? I've tried various combinations, including using time.sleep() before try rather than after except.

Thanks

Yes, the idea is that it waits 2 seconds before trying again, unless there's something wrong in the implementation? — user3294195, Mar 30 '14 at 07:57
I think I was confused by the wording of "executes after an element is confirmed present". My previous comment was an error. — , Mar 30 '14 at 07:58
Are you sure that the exception that you would expect it to throw is occurring in the `try` block? — anon582847382, Mar 30 '14 at 07:59
Yes. However, I've also tried `except` without explicitly referencing the exception. Still doesn't work... — user3294195, Mar 30 '14 at 08:01

neoascetic · Accepted Answer · 2022-11-28T07:56:59.863

35

The answer on your specific question is:

from selenium.common.exceptions import NoSuchElementException

link = None
while not link:
    try:
        link = driver.find_element_by_xpath(linkAddress)
    except NoSuchElementException:
        time.sleep(2)

However, there is a better way to wait until element appears on a page: waits

edited Nov 28 '22 at 07:56

answered Mar 30 '14 at 08:05

neoascetic

2,476
25
34

This works perfectly...Thanks very much! Seems like the error had to do with the logic behind the iteration. – user3294195 Mar 30 '14 at 08:10

Charls · Answer 2 · 2016-02-04T18:49:28.437

8

Another way could be.

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

try:
    element = WebDriverWait(driver, 2).until(
            EC.presence_of_element_located((By.XPATH, linkAddress))
    )
except TimeoutException as ex:
            print ex.message

Inside the WebDriverWait call, put the driver variable and seconds to wait.

edited Feb 04 '16 at 18:49

answered Jan 19 '16 at 23:01

Charls

81
1
2

This does not work for me. Error message: `NameError: global name 'TimeoutException' is not defined`. I think for this example to work you'd at least need to `import selenium` and then replace line 5 by `except selenium.common.exceptions.TimeoutException as ex:`. – altabq Feb 02 '16 at 09:52
yes, you need. from selenium.common.exceptions import TimeoutException – Charls Feb 03 '16 at 16:59

Python Selenium Webdriver - Try except loop

2 Answers2

Linked