[Python-Dev] Proposed Python api for testing whether a module exists

[Jim Fulton]

Anthony Baxter wrote:
> Jim Fulton wrote:
> 
>>      If a dotted module name is given, then parent modules will be
>>      imported if they haven't already been imported.
> 
> 
> So you might end up spelling something like:
> 
> if imp.exists('pkg') and imp.exists('pkg.subpkg') \
>      and imp.exists('pkg.subpkg.module'):
> 
> to avoid an importerror on the parent module?

No. If pkg doesn't exist then exists will report False.

Here's new wording:

    exists(module_name)

      Test whether the named module can be found.

      This method should be used when you want to perform
      alternate actions depending on whether a module is available.

      Returns True of the module can be found and False otherwise.
      A True return value does not guarentee that the module will be
      importable.  The module will not be imported as a result of
      calling exists, but parent modules may be.

      If a dotted module name is given and parent modules exist,
      then the parent modules will be imported if they haven't
      already been imported.

Thanks,

Jim

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