Good python equivalent to C goto

info at orlans-amo.be info at orlans-amo.be
Sun Aug 17 20:15:39 CEST 2008


On Aug 17, 8:09 pm, Matthew Fitzgibbons <eles... at nienna.org> wrote:
> Kurien Mathew wrote:
> > Hello,
>
> > Any suggestions on a good python equivalent for the following C code:
>
> > while (loopCondition)
> > {
> >     if (condition1)
> >         goto next;
> >     if (condition2)
> >         goto next;
> >     if (condition3)
> >         goto next;
> >     stmt1;
> >     stmt2;
> > next:
> >     stmt3;
> >     stmt4;
> >  }
>
> > Thanks
> > Kurien
> > --
> >http://mail.python.org/mailman/listinfo/python-list
>
> I would not be too happy if I saw C code like that in my repository.
> This is equivalent:
>
> while (loopCondition) {
>      if (!(condition1 || condition2 || condition3)) {
>          stmt1;
>          stmt2;
>      }
>      stmt3;
>      stmt4;
>
> }
>
> In Python:
>
> while (loopCondition):
>      if not (condition1 or condition2 or condition3):
>          stmt1
>          stmt2
>      stmt3
>      stmt4
>
> If stmt3 and stmt4 are error cleanup code, I would use try/finally.
>
> while loopCondition:
>      try:
>          if condition1:
>              raise Error1()
>          if condition2:
>              raise Error2()
>          if condition3:
>              raise Error3()
>          stmt1
>          stmt2
>      finally:
>          stmt3
>          stmt4
>
> This will also bail out of the loop on and exception and the exception
> will get to the next level. If you don't want that to happen, put an
> appropriate except block before the finally.
>
> -Matt- Hide quoted text -
>
> - Show quoted text -

class Goto_Target(Exception):
    pass

def Goto_is_not_dead(nIn):
    try:
        if (nIn == 1): raise Goto_Target
        if (nIn == 2): raise Goto_Target

        inv = 1.0 / nIn
        print 'Good Input ' + str(nIn) + ' inv=' + str(inv)

    except Goto_Target:
        pass
    except Exception, e:
        print 'Error Input ' + str(nIn) + ' ' + str(e)
    finally:
        print 'any input ' + str(nIn)

if __name__ == '__main__':
    Goto_is_not_dead(0)
    Goto_is_not_dead(2)
    Goto_is_not_dead(3)



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