My structure looks something like this:
project/->
app.py
checker/->
exc.py
anc.py
My files are simple:
# app.py
from checker.exc import ExampleClass
# checker/exc.py:
from anc import AnotherClass
class ExampleClass(AnotherClass):
print('Example')
# checker/anc.py:
class AnotherClass:
print('AAAA')
When I run exc.py inside checker folder everything works ok, same when
I run app.py with module from package checker everything works perfect.
But when I run app.py which uses class from checker.exc, and exc need anc. I have an error ModuleNotFoundError: No module named anc
Realise this is a duct tape solution.
Change exc.py to:
try:
from anc import AnotherClass
print('abs import')
except ModuleNotFoundError:
from .anc import AnotherClass
print('rel import')
class ExampleClass(AnotherClass):
print('Example')
That way you can use absolute import when debugging, for instance, but rely on relative import when importing it running app.py on it's own.
The order in which you attempt to import them should reflect the expected use, with the one most expected to be used being attempted first. The error is the same if you switch the attempts.
Since the code is being run from the project folder, in order for exc.py to find anc.py you need to change exc.py to the following:
from .anc import AnotherClass
class ExampleClass(AnotherClass):
print('Example')
As berna1111's comment suggests, this may cause problems when running exc.py directly.
Related
I'm using Python 3.9.5.
Based on this post, I'm trying to reuse some functions from the parent directory. Here's my code hierarchy:
github_repository
src
base
string_utilities.py
validation
email_validator.py
I also have __init__.py in all folders. In ALL of them.
Here's the string_utilities.py content:
def isNullOrEmpty(text: str):
return text is not None and len(text) > 0
And here's the email_validator.py content:
from src.base import string_utilities
def is_email(text: str):
if string_utilities.isNullOrEmpty(text):
return False
# logic to check email
return True
Now when I run python email_validator.py, I get this error:
ModuleNotFoundError: No module named 'src'
I have changed that frustrating import statement to all of these different forms, and I still get no results:
from ...src.base import string_utilities
which results in:
ImportError: attempted relative import with no known parent package
import src.base.string_utilities
Which causes compiler to not know the isNullOrEmpty function.
import ...src.base.string_utilities
Which results in:
Relative imports cannot be used with "import .a" form; use "from . import a" instead
I'm stuck at this point on how to reuse that function in this file. Can someone please help?
I'm new to python and I'm having this problem that I can't figure it out.
My file structure is:
enter image description here
On Criador.py I have several functions, for example:
def doSomething():
pass
def doSomethingElse():
pass
and Im trying to use one of this functions on the Controller.py file:
The first thing I did was, on the Controller.py:
import Controller.Criador
and then tried to use that function as:
Controller.Criador.doSomething()
After running Controller.py, I got this error:
ModuleNotFoundError: No module named 'Controller.Criador'; 'Controller' is not a package
I tried several other things, like:
from . import Criador
or
from Controller.Criador import doSomething
or
from Controller import Criador
and nothing helped, just changed the errors to:
ImportError: cannot import name 'Criador'
and
ModuleNotFoundError: No module named 'Controller.Criador'; 'Controller' is not a package
and
ImportError: cannot import name 'Criador'
Can someone give me a light about this? I'm using PyCharm and it does not give me any error when I declare the imports, only when I run the file
If Controller.py and Criador.py are in the same folder, you can do this inside Controller.py:
import Criador
Criador.doSomething()
New to Python I'm trying to setup a simple OOP-structure of files, folders and classes. Here are the file paths:
C:\Users\Mc_Topaz\Programmering\Python\Terminal\Main.py
C:\Users\Mc_Topaz\Programmering\Python\Terminal\Connections\Connection.py
C:\Users\Mc_Topaz\Programmering\Python\Terminal\Connections\NoConnection.py
Notice Connection.py and NoConnection.py is loacted in sub folder Connections.
Connection.py
class Connection:
def __init__(self):
pass
def ToString(self):
pass
NoConnection.py
from Connection import Connection
class NoConnection(Connection):
def __init__(self):
pass
def ToString(self):
print("No connection")
In the Main.py file I would like to call the ToString() method from each class.
Main.py
from Connections.Connection import Connection
from Connections.NoConnection import NoConnection
connection = Connection()
print(connection.ToString())
noConnection = NoConnection()
print(noConnection.ToString())
When I run the Main.py file I get this error:
C:\Users\Mc_Topaz\Programmering\Python\Terminal>Main.py Traceback
(most recent call last): File
"C:\Users\Mc_Topaz\Programmering\Python\Terminal\Main.py", line 2, in
from Connections.NoConnection import NoConnection
File
"C:\Users\Mc_Topaz\Programmering\Python\Terminal\Connections\NoConnection.py",
line 1, in
from Connection import Connection
ImportError: No module named 'Connection'
It seems that the interpreter cannot import the NoConnection class in my Main.py file due to it cannot import the Connection class from the NoConnection.py file.
I can run Connection.py and NoConnection.py separately with no problems.
I don't understand why the Main.py don't run. I assume is something super simple and I cannot see it due to I'm to green to Python.
For python to recognize a directory is a module, or a collection of python files, that directory must contain a file named __init__.py. That file doesn't need to contain anything code whatsoever, though it can. If you add this file to your Connections directory, the interpreter should be able to import the contained files.
Just to add on to what mobiusklein mentioned: a common practice with __init__.py is to import the objects you use most frequently to avoid redundancy in your imports. In your example your Connections\__init__.py would likely contain:
import Connection
import NoConnection
Then your Main.py could use the following import statements successfully:
from Connections import Connection, NoConnection
I think it's down to relative imports in Python 3.
Change the import line in NoConnection to be explicit...
from Connections.Connection import Connection
and it works in Python3 (it works either way in Python2). Path to Terminal may have to be on you PYTHONPATH environment variable.
"Python 3 has disabled implicit relative imports altogether; imports are now always interpreted as absolute, meaning that in the above example import baz will always import the top-level module. You will have to use the explicit import syntax instead (from . import baz)." from here https://softwareengineering.stackexchange.com/questions/159503/whats-wrong-with-relative-imports-in-python
So when you import Connection from NoConnection it will be looking for it at the Terminal level, not at the Terminal/Connections level.
UPDTAE: Read comments for this post as it contain the solution.
Still don't get this to work. But I have made some changes:
Changed names of classes
> Class Connection = Foo inside Connection.py
> NoConnection = Bar inside NoConnection.py
This is ensure that the interpreter don't get confused if Connection is a module or a class.
Dropped ini.py file
I have dropped the Connections\__init_.py file as this don't seem to be necessary in Python version 3.4.2.
Files still run separately
I can run Connection.py and NoConnection.py separately. So they work.
Main.py
from Connections.NoConnection import Bar
noConnection = Bar()
print(noConnection.ToString())
When running Main.py I get the same error at line 1:
"Cannot find module 'Connection' in NoConnection.py at line 1".
The only logical reason I can see why this error happens is:
The interpreter looks for Connection.py inside my Terminal folder as Python was started from that folder. Even if it's importing the NoConnection.py file from the Connections folder where Connection.py is located.
Is this a bug?
I have a module called spellnum. It can be used as a command-line utility (it has the if __name__ == '__main__': block) or it can be imported like a standard Python module.
The module defines a class named Speller which looks like this:
class Speller(object):
def __init__(self, lang="en"):
module = __import__("spelling_" + lang)
# use module's contents...
As you can see, the class constructor loads other modules at runtime. Those modules (spelling_en.py, spelling_es.py, etc.) are located in the same directory as the spellnum.py itself.
Besides spellnum.py, there are other files with utility functions and classes. I'd like to hide those files since I don't want to expose them to the user and since it's a bad idea to pollute the Python's lib directory with random files. The only way to achieve this that I know of is to create a package.
I've come up with this layout for the project (inspired by this great tutorial):
spellnum/ # project root
spellnum/ # package root
__init__.py
spellnum.py
spelling_en.py
spelling_es.py
squash.py
# ... some other private files
test/
test_spellnum.py
example.py
The file __init__.py contains a single line:
from spellnum import Speller
Given this new layout, the code for dynamic module loading had to be changed:
class Speller(object):
def __init__(self, lang="en"):
spelling_mod = "spelling_" + lang
package = __import__("spellnum", fromlist=[spelling_mod])
module = getattr(package, spelling_mod)
# use module as usual
So, with this project layout a can do the following:
Successfully import spellnum inside example.py and use it like a simple module:
# an excerpt from the example.py file
import spellnum
speller = spellnum.Speller(es)
# ...
import spellnum in the tests and run those tests from the project root like this:
$ PYTHONPATH="`pwd`:$PYTHONPATH" python test/test_spellnum.py
The problem
I cannot execute spellnum.py directly with the new layout. When I try to, it shows the following error:
Traceback (most recent call last):
...
File "spellnum/spellnum.py", line 23, in __init__
module = getattr(package, spelling_mod)
AttributeError: 'module' object has no attribute 'spelling_en'
The question
What's the best way to organize all of the files required by my module to work so that users are able to use the module both from command line and from their Python code?
Thanks!
How about keeping spellnum.py?
spellnum.py
spelling/
__init__.py
en.py
es.py
Your problem is, that the package is called the same as the python-file you want to execute, thus importing
from spellnum import spellnum_en
will try to import from the file instead of the package. You could fiddle around with relative imports, but I don't know how to make them work with __import__, so I'd suggest the following:
def __init__(self, lang="en"):
mod = "spellnum_" + lang
module = None
if __name__ == '__main__':
module = __import__(mod)
else:
package = getattr(__import__("spellnum", fromlist=[mod]), mod)
OK, I have the following directory structure (it's a django project):
-> project
--> app
and within the app folder, there is a scraper.py file which needs to reference a class defined within models.py
I'm trying to do the following:
import urllib2
import os
import sys
import time
import datetime
import re
import BeautifulSoup
sys.path.append('/home/userspace/Development/')
os.environ['DJANGO_SETTINGS_MODULE'] = 'project.settings'
from project.app.models import ClassName
and this code just isn't working. I get an error of:
Traceback (most recent call last):
File "scraper.py", line 14, in
from project.app.models import ClassName
ImportError: No module named project.app.models
This code above used to work, but broke somewhere along the line and I'm extremely confused as to why I'm having problems. On SnowLeopard using python2.5.
import sys
sys.path.append ('/path/to/the/project')
from django.core.management import setup_environ
import settings
setup_environ(settings)
from app.models import MyModel
Whoa whoa whoa. You should never ever have to put your project name in any of your app code. You should be able to reuse app code across multiple projects with no changes. Pinax does this really well and I highly recommend checking it out for a lot of django best practices.
The worst thing you could do here is to hard code your absolute path into your app or settings. You shouldn't do this because it will break during deployment unless you do some import local_settings hacking.
If you have to access the project root directory, try what pinax has in settings.py...
import os.path
PROJECT_ROOT = os.path.abspath(os.path.dirname(__file__))
The thing is that it looks like you are trying to access the models module within the same app and this is waaay easier.
To import models.py inside scraper.py in the same directory just use import models or import models as app_models if you already have something named models in scraper.py (django.db.models for instance). Are you familiar with Python module conventions?
However, the best way is probably to stick with the django idiom, from ... import ... statement:
from app import models
If this doesn't work automatically, then something is wrong in your settings.py.
You don't indicate if project is located in /home/userspace/Development/. I'll assume that it is.
Make sure there's an (empty by default) file named __init__.py in project and another one in app.
EDIT: Next thing to try: Fire up the Python command line in the script's directory and try the following:
import project
import project.app as app
import project.app.models as models
models.__dict__.keys()
Do they all work? If so, what is the last line's output? If not, which dies first?