exit 2 levels of if/else and execute common code

[Chris Angelico]

On Tue, Feb 12, 2019 at 3:21 AM Neal Becker <ndbecker2 at gmail.com> wrote:
>
> Chris Angelico wrote:
>
> > On Tue, Feb 12, 2019 at 2:27 AM Neal Becker <ndbecker2 at gmail.com> wrote:
> >>
> >> I have code with structure:
> >> ```
> >> if cond1:
> >>   [some code]
> >>   if cond2: #where cond2 depends on the above [some code]
> >>     [ more code]
> >>
> >>   else:
> >>     [ do xxyy ]
> >> else:
> >>   [ do the same xxyy as above ]
> >> ```
> >>
> >> So what's the best style to handle this?  As coded, it violates DRY.
> >> Try/except could be used with a custom exception, but that seems a bit
> >> heavy
> >> handed.  Suggestions?
> >
> > One common way to do this is to toss a "return" after the cond2 block.
> > Means this has to be the end of a function, but that's usually not
> > hard. Or, as Rhodri suggested, refactor xxyy into a function, which
> > you then call twice.
> >
> > ChrisA
>
> Not bad, but turns out it would be the same return statement for both the
> normal return path (cond1 and cond2 satisfied) as well as the abnormal
> return, so not really much of an improvement.

Not sure what you mean there. The result would be something like this:

def frobnicate():
    if cond1:
        do_stuff()
        if cond2:
            do_more_stuff()
            return
    do_other_stuff()

ChrisA