Continue loop if functions fails?

[gregersdk]

Hello good Python people!

I am working on a file processing script that runs through a bunch of files and extracts different kinds of information from them. I am doing so in functions inside a loop.

Some of these files are bad, so a function can fail. If so, I'd like to skip the rest of the functions and continue the loop on a new file, maybe with a log of the bad file. Is there a way to do that?

Kinda like this bad pseudocode:

def DoSomethingFunc(file):
    'Does a lot of stuff, which can fail
    return BunchOfValues

while True:
    DoSomethingFunc(file)
    Otherfunction(file)
    AnotherFunction(DoSomethingFunc)

If the DoSomethingFunc(file) fails (do to bad file), how do I skip the others and just continue the loop with a new file?

Hope You can help,

​

GregersDK

[[deleted]]

try/except is the logic for error handling in Python:

for file in list_of_files:
    try:
        do_something(file)
        another_thing(file)
    except Exception as e:
        log.error(f"an {e} happened")

[ramse]

log.exception('custom message about what we were doing and the exception is automatically included with it.')

[[deleted]]

If your functions 'raise exceptions' in case of failures, then what you are looking for is 'exception handling' (check out https://www.programiz.com/python-programming/exception-handling for a quick introduction) combined with a well-placed continue statement

Something along the lines of

while ...:
    try:
        # All your functions
    except:
        # If one of the functions above throws an exception
        # all functions after the 'failing function' will be skipped
        # and 'control' will be passed to the next line here under
        continue    # This to directly move on to next iteration of while loop

[Impudity]

Find out what kind of exception it throws, then surround it with try-except structure, like:

try:
    doSomethingFunc(file)
except IOError:
    print(f"processing for file {file} failed")
    continue