Develop Reference

How to import a python function from a sibling folder

This question has been asked before. Even though I couldn't get an answer that solves this issue.
I have the following directory and subdirectories:
I have a function hello() in test1.py that I want to import in test2.py.
test1.py:
def hello():
print("hello")
test2.py:
import demoA.test1 as test1
test1.hello()
Output:
Traceback (most recent call last):
File "c:/Users/hasli/Documents/Projects/test/demoB/test2.py", line 1, in <module>
import demoA.test1 as test1
ModuleNotFoundError: No module named 'demoA'
This is exactly as explained in https://www.freecodecamp.org/news/module-not-found-error-in-python-solved/ but I can't access hello()
I am using python 3: Python 3.8.9

You need to add demoA to the list of paths used for import.
import sys
sys.path.append('..')
import demoA.test1 as test1
test1.hello()

Is it possible to import a python file from outside the directory the main file is in?

I have a file structure that looks like this:
Liquid
|
[Truncate]
|_General_parsing
[Truncate]
.....|_'__init__.py'
.....|_'Processer.py'
.....|'TOKENIZER.py'
|_'__init__.py'
|_'errors.py'
[Truncate]
I want to import errors.py from Processer.py. Is that possible? I tried to use this:
from ..errors import *; error_manager = errorMaster()
Which causes this:
Traceback (most recent call last):
File "/Users/MYNAME/projects/Liquid/General_parsing/Processer.py", line 17, in <module>
from ..errors import *; error_manager = errorMaster()
ImportError: attempted relative import with no known parent package
[Finished in 0.125s]
I've seen this post, but it's no help, even if it tries to solve the same ImportError. This isn't, either (at least not until I edited it), since I tried:
import sys
sys.path.insert(1, '../Liquid')
from errors import *; error_manager = errorMaster()
That gives
Traceback (most recent call last):
File "/Users/MYNAME/projects/Liquid/General_parsing/Processer.py", line 19, in <module>
from errors import *; error_manager = errorMaster()
ModuleNotFoundError: No module named 'errors'
[Finished in 0.162s]
EDIT: Nevermind! I solved it! I just need to add .. to sys.path! Or . if .. doesn't solve your problem. But if those don't solve your problem: use some pathlib (came in python3.4+) magic and do:
from pathlib import Path
import sys
sys.path.insert(0, str(Path(__file__).parent))
or, if you want to use os: (gotten from this StackOverflow answer)
import os
os.path.join(os.path.dirname(__file__), '..')

I solved it! I have to add .. to sys.path instead

How to import a module from sub directory

I failed to import a module from sub directory in python. Below is my project structure.
./main.py
./sub
./sub/__init__.py
./sub/aname.py
when I run python main.py, I got this error:
Traceback (most recent call last):
File "main.py", line 4, in <module>
import sub.aname
File "/Users/dev/python/demo/sub/__init__.py", line 1, in <module>
from aname import print_func
ModuleNotFoundError: No module named 'aname'
I don't know it failed to load the module aname. Below is the source code:
main.py:
#!/usr/bin/python
import sub.aname
print_func('zz')
sub/__init__.py:
from aname import print_func
sub/aname.py:
def print_func( par ):
print ("Hello : ", par)
return
I am using python 3.6.0 on MacOS

There are several mistakes in your Python scripts.
Relative import
First, to do relative import, you must use a leading dots (see Guido's Decision about Relative Imports syntax).
In sub/__init__.py, replace:
from aname import print_func
with:
from .aname import print_func
Importing a function
To import a function from a given module you can use the from ... import ... statement.
In main.py, replace:
import sub.aname
with:
from sub import print_func

from sub import aname
aname.print_func('zz')

Probably the most elegant solution is to use relative imports in your submodule sub:
sub.__init__.py
from .aname import print_func
But you also need to import the print_func in main.py otherwise you'll get a NameError when you try to execute print_func:
main.py
from sub import print_func # or: from sub.aname import print_func
print_func('zz')

Module has no attribute error in python3

contents of io.py
class IO:
def __init__(self):
self.ParsingFile = '../list'
def Parser(self):
f = open(ParsingFile, 'r')
print(f.read())
contents of main.py
import sys
sys.path.insert(0, "lib/")
try:
import io
except Exception:
print("Could not import one or more libraries.")
exit(1)
print("Libraries imported")
_io_ = io.IO()
When I run python3 main.py I get the following error:
Libraries imported
Traceback (most recent call last):
File "main.py", line 11, in <module>
_io_ = io.IO()
AttributeError: module 'io' has no attribute 'IO'
Any idea what's going wrong?

My file was called io. It seems that there already exists a package called io which caused the confusion.

Your package name (io) conflicts with the Python library's package with the same name, so you actually import a system package.
You can check this by printing io.__all__.
Changing io.py to something else is probably the best way to go to avoid similar problems. Otherwise, you can use an absolute path.

try
from io import IO
That worked for me when trying to import classes from another file
this has more information:
Python module import - why are components only available when explicitly imported?

error when using import command in python

I'm new to python and now learning how to to import a module or a function, but I got these posted errors. The python code is saved under the name: hello_module.py
python code:
def hello_func():
print ("Hello, World!")
hello_func()
import hello_module
hello_module.hello_func()
error message:
Traceback (most recent call last):
File "C:/Python33/hello_module.py", line 9, in <module>
import hello_module
File "C:/Python33\hello_module.py", line 10, in <module>
hello_module.hello_func()
AttributeError: 'module' object has no attribute 'hello_func'

You cannot and should not import your own module. You defined hello_func in the current namespace, just use that directly.
You can put the function in a separate file, then import that:
File foo.py:
def def hello_func():
print ("Hello, World!")
File bar.py:
import foo
foo.hello_func()
and run bar.py as a script.
If you try to import your own module, it'll import itself again, and when you do that you import an incomplete module. It won't have it's attributes set yet, so hello_module.hello_func doesn't yet exist, and that breaks.