Saturday, March 03, 2007

The Implied Module Path

We all know there is an implied path to import from for the main module, but it seems a few people get mixed about the details of how this works. In particular, it seems that this path is being confused for the current working directory. Here is a little note to help remember the distinction.
  • Any module implicitly can import packages and modules in the same directory its file resides in, which is os.path.dirname(the_module.__file__)
  • Often you run a script, when starting out, from its own directory, so that this implied path is the current working directory. This fact is purely a coincidence.
The result boils down simply to understanding that any import can be relative to the module it appears in, and if you run a local (not system-wide available) script, that just happens to be your current directory, by coincidence.
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I am happily employed by the excellent Caktus Group, located in beautiful and friendly Carrboro, NC, where I work with Python, Django, and Javascript.