On Mon, 10 Nov 2014 16:12:07 +1100, Ben Finney <[email protected]> wrote:
>Steve Hayes <[email protected]> writes: > >> I have a book on Python that advocates dividing programs into modules, >> and importing them when needed. > >Which book is this? (This is not essential to your question, but it >might help to gauge your broader learning environment.) Cunningham, Katie. 2014. Teach yourself Python in 24 hours. Indianapolis: Sams. ISBN: 978-0-672-33687-4 For Python 2.7.5 >> I can understand doing that in a compiled language, where different >> modules can be imported from all sorts of places when the program is >> compiled. > >Python is a compiled language; when you run a Python program a necessary >step is to compile the Python source to a bytecode for actual execution. > >Usually, the compilation step is done dynamically; but (barring >contrived examples) it is always done prior to running the program. > >> But I understand that Python is an interpreted language > >The two are not mutually exclusive. The Python interpreter works with >compiled Python code, it does not execute the source directly. > >> If I wrote a program in Python like that, and wanted to run it on >> another computer, how would it find all the modules to import at >> run-time, unless I copied the whole directory structure over to the >> other computer? > >That's the idea, yes. You need to distinguish between: > >* The standard library: installed along with the Python interpreter when > you install that, and available on the default module search path. > >* Third-party modules: installed using your package manager (ideally by > the operating system package manager), again to a location already > part of the default module search path on your system. > >* Modules specific to the application you're writing: Keep these in a > known hierarchy, and use the distribution tools to package them to > keep them together when distributing to oher machines. > >Use abolute import for standard library and third-party modules. Use >relative import for application-private modules. > >This ensures your aplication's private modules don't conflict with >current or future names of modules from the standard library or third >parties. So if I want to run it on another computer, where do I look for the compiled executable program to copy? -- Steve Hayes from Tshwane, South Africa Web: http://www.khanya.org.za/stevesig.htm Blog: http://khanya.wordpress.com E-mail - see web page, or parse: shayes at dunelm full stop org full stop uk -- https://mail.python.org/mailman/listinfo/python-list
