Testing the availability of a module

[Gerhard Häring]

Bo Peng wrote:
> Dear list,
> 
> Is there a better way than doing
> 
> try:
>    import aModule
> except:
>    has_aModule = False
> else:
>    has_aModule = True
> 
> The main concern here is that loading aModule is unnecessary (and may 
> take time).

No, there is not really a better way.

You *could* check for the existance of files, but a file existing and it 
really being successfully loadable as a module are not the same.

Besides, it is a lot of work to reimplement half the Python import 
machinery just for checking for all kinds of files. If you're serious 
about it, you also need to cope with modules loadable from ZIP files, 
and with .pth files, etc.

This is not fun to program, and you're really better off just checking 
for a successful import like you're doing now.

-- Gerhard