Kermit Rose wrote:
>
>
> From: Alan Gauld
> Date: 08/14/06 18:42:41
> To: Kermit Rose; Luke Paireepinart
> Cc: tutor@python.org; Danny Yoo
> Subject: Re: [Tutor] Global variables
>
>
> That may be true but you will make your code much less reusable
> and much more error propne in the process. There are good reasons
> why global variables are considered evil...
>
>
> *****
>
> I know that global variable usage can be abused.
>
> But in fact I use the same variable names in the subroutine parameter list
> as in the calling routine for every function in the module.
>
> So I believe that in this case global variables would be useful and not
> likely to
> increase errors due to confusion of global and local variables.
>
> I would never have a local variable with the same name as the global
> variable.
>
>
It sounds like you should make a Factoring class and have whichever
variables are similar for all functions be variables specific to the
class instance
(I forgot the word for this)
Something like:
#----
Class Factoring(object):
def __init__(self):
self.var1 = ['a','b','c']
self.var2 = 5
self.var3 = (0)
def method1(self):
print self.var1,self.var2
def method2(self):
print self.var2,self.var3
fac = Factoring()
fac.method1()
fac.method2()
#-----
the output would be
['a','b','c']5
5(0)
Thus you prevent global namespace pollution.
> But in this case, it's only because of an apparent bug in Python that want
> to
> bypass that I'm considering the use of global variables.
>
You probably shouldn't claim there's a bug in Python unless you're sure
(I.E. have a snippet of code
that reproduces the bug that you'll share with us)
>
>
> My routine strongfac calculates a value for fac in the subroutine, and the
> calling routine picks up a different vaalue.
>
do you think you could use more conventional terminology like 'function'
and such?
I don't understand what you mean by the subroutine of the routine.
def routine():
def subroutine():
print 'hi'
subroutine()
Is that what you mean?
or by 'subroutine' do you mean 'loop inside of function'?
By your terminology, if there's a routine that calls strongfac, doesn't
that mean
strongfac is a subroutine? which would mean that the value for fac is
calculated in the subroutine of the subroutine of the calling routine?
>
> An illustration.
>
> In strong fac:
>
> fac = [1,2,3]
> print fac
> return fac
>
> in fermat:
>
> fac = strongfac(z)
> print fac
>
> prints [0,0,0]
>
what is 'z'? a random parameter?
can you give us a cut-down version of your code that just reproduces this
erratic behavior you're having a problem with?
>
> And most of the time it does not misbehave like this.
>
if random.randint(0,5) < 3:
malfunction()
>
> It is only occasionally, and consistently with certain numbers to be
> factored.
>
so with certain numbers it always occurs, with other numbers it
sometimes occurs?
>
>
> Kermit < [EMAIL PROTECTED] >
>
>
Luke
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