[Tutor] Resuming one block of code continuously after exception in try/except construction

[Alan Gauld]

On 06/07/14 22:00, Ali Mammadov wrote:

> common pratice, I want my function to check user's input(in this case
> it's file name) and re-ask it again and again(until correct) offering
> him two choices: re-enter file name or close program.I've decided to use
> try/except construction in this particular task.

Thats the wrong solution.
try/except is for catching errors not repeating actions.
You need to combine the try/except with a loop.

> BTW, I created a small gist located here
> <https://gist.github.com/bca59570ea5fd365c672> which demonstrates my
> problem.

For short (<100lines) example just post it in your message, it saves a 
lot of extra jumping around. Here it is:

---------------
def makelgpwdcombs(brutelistname):
	try:
		blst = open(brutelistname, 'r')
	except:
		print("[-] Invalid file name or insufficient priviliges")
	else:
		print("[+] File opened. Working...")
--------------------

Drop the else clause and put the try/except inside a while...

def makelgpwdcombs(brutelistname):
     while True:
        try:
	  blst = open(brutelistname, 'r')
           break # exit loop if no error
        except:
           print("[-] Invalid file name or insufficient priviliges")

     print("[+] File opened. Working...")   # only after valid input

loops are for repeating, try/except is for catching errors.
Use the right tool for the job.

HTH
-- 
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
http://www.flickr.com/photos/alangauldphotos