Verificando em python3:
python -V
Python 3.6.5
Exemplo 1:
.
├── 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
Se rodarmos assim (apenas para garantir que PYTHONPATH esteja vazio):
PYTHONPATH='' python3 start.py
Resultado:
Traceback (most recent call last):
File "start.py", line 1, in <module>
import sub.relative
File "/python-import-examples/so-example-v1/sub/relative.py", line 1, in <module>
from .. import parent
ValueError: attempted relative import beyond top-level package
Se alterarmos a importação em sub/relative.py
- sub/relative.py
import parent
Se rodarmos assim:
PYTHONPATH='' python3 start.py
Resultado:
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
Execute-o como:
PYTHONPATH='' python3 sub/start.py
Resultado:
Hello from relative.py
Traceback (most recent call last):
File "sub/start.py", line 2, in <module>
from .. import parent
ValueError: attempted relative import beyond top-level package
Se alterarmos a importação em sub/start.py
:
- sub/start.py
import relative
import parent
Execute-o como:
PYTHONPATH='' python3 sub/start.py
Resultado:
Hello from relative.py
Traceback (most recent call last):
File "sub/start.py", line 3, in <module>
import parent
ModuleNotFoundError: No module named 'parent'
Execute-o como:
PYTHONPATH='.' python3 sub/start.py
Resultado:
Hello from relative.py
Hello from parent.py
Também é melhor usar a importação da pasta raiz, ou seja:
- sub/start.py
import sub.relative
import parent
Execute-o como:
PYTHONPATH='.' python3 sub/start.py
Resultado:
Hello from relative.py
Hello from parent.py