Dependency analysis programs help us organize code by controlling the dependencies between modules in our code. When one module is a circular dependency of another module, it is a clue to find a way to turn that into a unidirectional dependency or merge two modules into one module.
What is the best dependency analysis tool for Python code?
I don't know what is the best dependency analysis tool. You could look into modulefinder – it's a module in the standard library that determines the set of modules imported by a script.
Of course, with python you have problems of conditional imports, and even potentially scripts calling __import__ directly, so it may not find everything. This is why tools like py2exe need special help to cope with packages like PIL.
I recommend using snakefood for creating graphical dependency graphs of Python projects. It detects dependencies nicely enough to immediately see areas for refactorisation. Its usage is pretty straightforward if you read a little bit of documentation.
Of course, you can omit the graph-creation step and receive a dependency dictionary in a file instead.
PyStructure – Automated Structure and Dependency Analysis of Python Code
This is used for PyDev's refactoring features. http://pystructure.ifs.hsr.ch/trac/