Creating objects you don't actually want

Chris Lyon chris.lyon at spritenote.co.uk
Tue Feb 10 11:50:13 CET 2004


If you wish to create an object:- 

for item in os.listdir('dir'):
    sfx = sfxobject(item)


class sfxobject(object):
    def __init__(self, filename):
        if isfile(filename):
            self.filename = filename
            # all kinds of other parameter setting

If the creation fails for any reason you are left with an object which
is not really a 'proper' object how is it best to deal with this
circumstance?

Do you raise an exception and perform the creation line within a try:
except: and then delete it?


class sfxobject(object):
    def __init__(self,filename):
        if isfile(filename):
            self.filename = filename
            # all kinds of other parameter setting
         else:
            raise sfxobjectError

for item in os.listdir('dir'):
    try:
        sfx = sfxobject(item)
    except: sfxobjectError
        del sfx

or should you heavily check the parameter before you try to create the
object?

for item in os.listdir('dir'):
    if os.isfile(item):  
        sfx = sfxobject(item)

I would think that this second method should really have all the
checking within the object it's self but then of course you have to
create the object to allow you to do the checks and you will still be
left with an inapproriate object to clean up afterwards?

No doubt there are many other ways of addressing this but it's a
problem I would love to have a deffinative answer to, unless of course
there isn't one.



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