CODEWITHSUNDEEP
python
Yifei
Yifei

Reputation: 1944

Equivalent of GOTO in Python exception handling

I will have the following code structure in my Python script. But goto is ugly and not allowed to use in Python.

Could some one can suggest a prettier and more pythonic flow design to accomplish this?

PS: I tried to use recursive function call in exception handler, but the program ate plenty of memory after a while.

try:
    # label: log_in
    login_to_system()
    # label: run
    while True:
        query()
        calculate()
        update()
    # Network exceptions might occur during login and query/update
    # Other exceptions might occur during query/calculate/update but do not need to login again.

except SomeNetworkException:
    # Need to log in to system again
    go to: label log_in
except OtherExceptions:
    go to: label run

Updated:

In this case, Network exceptions handler is "shared" by both login and other functions.

Previously, I wrapped login_to_system() function with a try/except block and wrote the same code in login's exception handler, but I felt it was ugly to have the same exception handler code twice in this block.

Upvotes: 0

Views: 3507

Answers (1)

georg
georg

Reputation: 215029

I'd rewrite this logic in the following way: move exception handling into the loop and on each iteration check if you need to login:

needs_login = True

while True:

    try:

        if needs_login:
            login_to_system()
            needs_login = False

        query()
        calculate()
        update()

    except SomeNetworkException:
        needs_login = True

    except OtherExceptions:
        pass

Upvotes: 2

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