Python-接下来在for循环中尝试

Question

I have a for loop that itterates over a list of URLS. The urls are then loaded by the chrome driver. Some urls will load a page that is in a 'bad' format and it will fail the first xpath test. If it does I want it to go back to the next element in the loop. My cleanup code works but I can't seem to get it to go to next element in the for loop. I have an except that closes my websbrowser but nothing I tried would all me to then loop back to 'for row in mysql_cats'

for row in mysql_cats : 
   print ('Here is the url -', row[1])
   cat_url=(row[1])
   driver = webdriver.Chrome()
   driver.get(cat_url); #Download the URL passed from mysql

   try:   
      CategoryName= driver.find_element_by_xpath('//h1[@class="categoryL3"]|//h1[@class="categoryL4"]').text   #finds either L3 or L4 catagory 
   except:
      driver.close()
      #this does close the webriver okay if it can't find the xpath, but not I cant get code here to get it to go to the next row in mysql_cats

Answer 1

I hope that you're closing the driver at the end of this code also if no exceptions occurs.
If you want to start from the beginning of the loop when an exception is raised, you may add continue , as suggested in other answers:

try:   
    CategoryName=driver.find_element_by_xpath('//h1[@class="categoryL3"]|//h1[@class="categoryL4"]').text   #finds either L3 or L4 catagory 
except NoSuchElementException:
    driver.close()
    continue # jumps at the beginning of the for loop

since I do not know your code, the following tip may be useless, but a common way to handle this cases is a try/except/finally clause:

for row in mysql_cats : 
    print ('Here is the url -', row[1])
    cat_url=(row[1])
    driver = webdriver.Chrome()
    driver.get(cat_url); #Download the URL passed from mysql
    try:
        # my code, with dangerous stuff
    except NoSuchElementException:
        # handling of 'NoSuchElementException'. no need to 'continue'
    except SomeOtherUglyException:
        # handling of 'SomeOtherUglyException'
    finally: # Code that is ALWAYS executed, with or without exceptions
        driver.close()

I'm also assuming that you're creating new drivers each time for a reason. If it is not voluntary, you may use something like this:

driver = webdriver.Chrome()
for row in mysql_cats : 
    print ('Here is the url -', row[1])
    cat_url=(row[1])
    driver.get(cat_url); #Download the URL passed from mysql
    try:
        # my code, with dangerous stuff
    except NoSuchElementException:
        # handling of 'NoSuchElementException'. no need to 'continue'
    except SomeOtherUglyException:
        # handling of 'SomeOtherUglyException'
driver.close()

In this way, you have only one driver that manages all the pages you're trying to open in the for loop

have a look somewhere about how the try/except/finally is really useful when handling connections and drivers.
As a foot note, I'd like you to notice how in the code I always specify which exception I am expecting: catching all the exception can be dangerous . BTW, probably no one will die if you simply use except:

Answer 2

Add continue to your except statement. The continue command moves you to the next cycle.