Module Loading and Compilation

So far, this chapter has presented modules as files containing Python code. However, modules loaded with import really fall into four general categories:

  • Programs written in Python (.py files)

  • C or C++ extensions that have been compiled into shared libraries or DLLs

  • Packages containing a collection of modules

  • Built-in modules written in C and linked into the Python interpreter

When looking for a module foo, the interpreter searches each of the directories in sys.path for the following files (listed in search order):

  1. A directory foo defining a package

  2. foo.so, foomodule.so, foomodule.sl, or foomodule.dll (compiled extensions)

  3. foo.pyo (only if the -O or -OO option has been used)

  4. foo.pyc

  5. foo.py

Packages are described ...

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