Can anyone explain python s relative imports

Question

I can t for the life of me get python s relative imports to work  I have created a simple example of where it does not function   The directory structure is      init   py  start py  parent py  sub   init   py  sub relative py    start py contains just  import sub relative   sub relative py contains just from    import parent  All other files are blank   When executing the following on the command line     cd     python start py   I get   Traceback  most recent call last     File  start py   line 1  in  lt module gt      import sub relative   File   home cvondrick sandbox sub relative py   line 1  in  lt module gt      from    import parent ValueError  Attempted relative import beyond toplevel package   I am using Python 2 6  Why is this the case  How do I make this sandbox example work

User · Answer

If you are going to call relative py directly and i e  if you really want to import from a top level module you have to explicitly add it to the sys path list  Here is how it should work       Add this line to the beginning of relative py file import sys sys path append          Now you can do imports from one directory top cause it is in the sys path import parent    And even like this  from parent import Parent   If you think the above can cause some kind of inconsistency you can use this instead     sys path append sys path 0             sys path 0  refers to the path that the entry point was ran from

User · Answer

You are importing from package  sub   start py is not itself in a package even if there is a   init   py present   You would need to start your program from one directory over parent py     start py    pkg   init   py   pkg parent py   pkg sub   init   py   pkg sub relative py   With start py   import pkg sub relative   Now pkg is the top level package and your relative import should work     If you want to stick with your current layout you can just use import parent  Because you use start py to launch your interpreter  the directory where start py is located is in your python path  parent py lives there as a separate module   You can also safely delete the top level   init   py  if you don t import anything into a script further up the directory tree

User · Answer

Checking it out in python3   python -V Python 3 6 5   Example1      -- parent py  -- start py  -- sub      -- relative py  - start py import sub relative  - parent py print  Hello from parent py    - sub relative py from    import parent   If we run it like this just to make sure PYTHONPATH is empty    PYTHONPATH    python3 start py   Output   Traceback  most recent call last     File  start py   line 1  in  lt module gt      import sub relative   File   python-import-examples so-example-v1 sub relative py   line 1  in  lt module gt      from    import parent ValueError  attempted relative import beyond top-level package   If we change import in sub relative py  - sub relative py import parent   If we run it like this   PYTHONPATH    python3 start py   Output   Hello from parent py   Example2      -- parent py  -- sub      -- relative py      -- start py  - parent py print  Hello from parent py    - sub relative py print  Hello from relative py    - sub start py import relative from    import parent   Run it like   PYTHONPATH    python3 sub start py   Output   Hello from relative py Traceback  most recent call last     File  sub start py   line 2  in  lt module gt      from    import parent ValueError  attempted relative import beyond top-level package   If we change import in sub start py   - sub start py import relative import parent   Run it like   PYTHONPATH    python3 sub start py   Output   Hello from relative py Traceback  most recent call last     File  sub start py   line 3  in  lt module gt      import parent ModuleNotFoundError  No module named  parent    Run it like   PYTHONPATH     python3 sub start py   Output   Hello from relative py Hello from parent py   Also it s better to use import from root folder  i e    - sub start py import sub relative import parent   Run it like   PYTHONPATH     python3 sub start py   Output   Hello from relative py Hello from parent py

[python] Can anyone explain python's relative imports?

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