Ritesh Raj Sarraf a écrit :
> On Aug 11, 3:17 am, James Stroud <[EMAIL PROTECTED]> wrote:
>> You do realize your import statement will only be called for nt and dos
>> systems don't you?
>>
>
> Yes. I would like to load a Windows Python Module (which is, say a
> specific implementation for Windows only) in such a condition where I
> find that the platform is Dos/NT.
>
> Loading it globally doesn't make sense because when from the same
> class an object is created on a non-windows platfom, it would be
> waste. It would either ImportError or else just load the module and
> never use it.
>
> As per my understanding __init__ is executed only once during object
> creation. For such situations (that I've explained above), I think
> __init__() is the correct place to put imports.
Nope.
The initializer will be called *each time* you instanciate the class.
And nothing prevents client code from calling it explicitelly as many
times as it wants - ok, this would be rather strange, but this is still
technically possible. What I mean that you have no assurance about the
number of times an initializer will be called.
wrt/ your problem, remember that top-level code is executed when the
module is loaded (either as a main program or as an imported module).
The canonical solution to os-specific imports is to handle them at the
top-level:
if os.name == 'posix:
from some_posix_module import get_colors
elif os.name in ['nt', 'dos']:
from some_nt_module import get_windows_color as get_colors
else:
get_colors = lambda: None # or any other sensible default value...
class SomeClass(object):
def __init__(self, *args, **kw):
self.colors = get_colors()
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