I'm having a hard time trying to import modules created inside a project.
The structure of my project is as follows:
myapp/calcs/__init__.py
myapp/calcs/calculations.py
myapp/tests/__init__.py
myapp/tests/test_calcs.py
Inside test_calcs.py, I have the following import statement:
from calcs import calculations as clc
However, I am getting this error:
ModuleNotFoundError: No module named calcs
I can't understand why I am having this error as I have included an init.py file inside calcs which should make it act as a module.
I also found this part of python extremely confusing. You basically need to make your project an installable package and do an editable install of it in your environment to import your modules this way. I would recommend this youtube video for a great walkthrough on the process, you only need to watch 2:36-8:36 for this topic specifically but the whole video is quite useful. Best of luck.
The first three answers in this thread describe how you can solve this pretty well!
Short version:
change from calcs import calculations as clc to from ..calcs import calculations as clc
start a terminal session in the parent folder of myapp
run python -m myapp.tests.test_calcs.py
Related
is it the "name" in the setup.py gets to be the name of the module?
so in this instance when i use this module is the code going to be written as "from myfirstmodule import siblings_game enter image description here?
the other modules ive tried creating have nor worked when applied to flask ( the next part of the textbook is to create a webapp) and i am trying to find the root of the priblem. idk if im not importing the right name.
Start at the start. All that's needed to write a module in Python is naming a file like my_mod.py:
print('Hello')
Now this code will execute the module (once):
import my_mod
If you have anything named in your module, it can be referenced on the module, or imported directly, like this other my_mod.py:
def fun():
...
ten = 10
Now this works:
import my_mod
my_mod.fun()
from my_mod import ten
print(ten)
Once you're comfortable with that, you can put the module in an appropriately named folder, add an __init__.py and you have the beginnings of a package. The package can be provided with a setup.py and that allows you to specify more relevant metadata about the package, like what its requirements are, what platform it is for, etc.
And once you have your package, you can turn that into a wheel (.whl) file, or publish it on a service like PyPI and use it in any other application, by installing it. That can be a web application, or any other type of application.
The name attribute is the name of your package. It is the identifier that you or someone else will have to import in order to use its functionality, just like you say:
import myfirstpackage
from myfirstpackage import myfirstfunction
If your package is not correctly imported, chances are that Python can find it from your working directory, or that your "package" isn't a package at all! (Have you added an __init__.py file to myfirstpackage/ ?)
Other than that, you may have to repost a question showing exactly what you are doing.
I have a project which worked perfectly fine, but I wanted to separate some of the code into a separate project (with its own packages). I have successfully done that, but now in that newly separated package I need to explicitly import local modules using from . import <module> instead of import <module> - the latter of which had worked before separating the modules into their own package.
The new imports (where I include the dot representing the local dir) works but it seems like it should also just work without having to specify the module locations since the files are in the same directory as the module that is trying to import them. Am I missing something here?
Artificial example:
|-root
|--ProjectA
|---app.py
|-root
|--ProjectB
|---ProjectB
|----__init__.py
|----libA.py
|----libB.py
In app.py I am able to import a module from ProjectB (I have adjusted PYTHONPATH to include /root/ProjectB). So the following works just fine as I would expect:
from ProjectB import libA.py
But the entire thing fails because in libA.py the following does not work:
import libB
Instead I have to use:
from . import libB
I have tried to wrap my head around how python imports work across packages and I thought I had sorted it in my head, but apparently I am missing something. Unless this is the way it is supposed to work? (packages need to explicitly indicate that a module is local). But I thought python would always implicitly add the path of the current module that is doing the importing.
Any advice (or even just links to tutorials that explain this - I have watched a lot but they all tend to focus on different aspects of importing than this) is greatly appreciated.
I'm trying to set up a roguelike Python project, but I can't seem to be able to import libtcod module into my project. This helloworld crashes, and the IDE keeps telling me that there is no module named libtcodpy.
import libtcodpy
def main():
print('Hello World!')
if __name__ == '__main__':
main()
What is the proper way to import modules into Python projects? I'm used to Java, so I was expecting something along the lines of Maven to manage the dependencies. There indeed seems to be something like that in PyCharm as well, this package manager for the venv, which from what I gather serves to isolate the project-specific stuff from the OS- or python-global stuff:
but libtcod simply isn't present in the rather exhaustive list of modules that appears after clicking on the "+" button, just some other module that has something to do with libtcod library (I guess?). Moreover, all the tutorials I found on setting libtcod up advise one to manually copy over files somewhere or run some command that I suppose does the importing somehow and other such solutions, all of which i tried and none of which worked. I don't want to pollute my project structure by using such hodgepodge ways of handling dependencies if I can at all avoid it.
Q: How do I get libtcod to work in my PyCharm project in the most clean and convention-abiding way possible?
Take a look at this github project called tcod: https://github.com/libtcod/python-tcod/blob/master/README.rst#installation
It's a python port of libtcod.
To install using pip, use the following command:
python -m pip install tcod
If you get the error "ImportError: DLL load failed: The specified module could not be found." when trying to import tcod/tdl then you may need the latest Microsoft Visual C runtime.
Blockquote
I am following the tutorial here:
http://www.prokopyshen.com/create-custom-zipline-data-bundle
and trying to set up a custom bundle to get price from custom, non US financial assets. I am stuck on the line that says:
Advise zipline of our bundle by registering it via .zipline/extension.py
My extension.py file is located in the .zipline/ directiory and has the following code:
from zipline.data.bundles import register
from zipline.data.bundles.viacsv import viacsv
eqSym = {
"CBA"
}
register(
'CBA.csv', # name this whatever you like
viacsv(eqSym),
)
I don't get what it means to register the bundle via .zipline/extension.py though? I thought it might mean to just run the extension.py file from my terminal via a:
python extenion.py
but that fails and says:
ImportError: No module named viacsv
How do i register this bundle?
I also followed this tutorial and I must confess this part is a little confusing.
First of all, I don't think it's necessary to run:
$ python extension.py
The error message you get probably comes from the fact that Python cannot find the viacsv.py file in sys.path (the places where it looks for modules, etc.). In the tutorial you mentioned, it's not really clear what to do with this file. As far as I am concerned, I just saved the viacsv.py file in my local site-packages directory. As I am on Linux I put it there ~/.local/lib/python2.7/site-packages but it might different for you. You can run the following python script to find out:
import sys
for dr in sys.path:
print dr
Then I just substituted from zipline.data.bundles.viacsv import viacsv with from viacsv import viacsv in extension.py.
I suspect you might be looking for the wrong place for the extension.py file.
For windows machine, the file is under "~\.zipline\extension.py". In my case, it's under "C:\Users\XXXX\.zipline\extension.py".
I had been looking at zipline folder under conda's site-packages folder, and couldn't find it. Then created an extension.py myself wondering why it's not called.
Check a related post here https://www.quantopian.com/posts/zipline-issue-while-creating-custom-bundle-to-bring-yahoo-data.
Same issue here, #Gillu13 pointed me to this solution.
I installed zipline through conda. So zipline is installed in
home/me/anaconda3/envs/krakenex/lib/python3.6/site-packages
in there you will find zipline/data/bundles and you can put viacsv.py in there...
then
from zipline.data.bundles.viacsv import viacsv
works
I have a Python library I wrote which has been acting up on me. I have a set of variables which change the way the library works. In testing it all worked fine, but when I python lib.py install the variables have no effect on the library. I broke this down to the simplest example possible:
Library:
##lib.py
config="Original"
def run():
print config
Script:
import lib
lib.config="New"
lib.run()
print lib.config
If you place the library in the same directory as the script and run it the output is:
New
New
But if you install the library and then try the script using the library from the dist-packages the output is:
Original
New
Could someone explain what is going on? I'm a bit confused and terribly interested in the happenings and reason. Additionally am I doing programatical configuration totally wrong?
Edit
It turns out the problem is the init.py file. It's basically like importing a library that just imports another library. When you import an installed module it looks at the folder lib and the file init.py. init.py is just a one liner from lib import *. It simply pretends to be the actual library, but that causes an odd problem if you use a global variable. A simulated example of what is essentially going on:
##init.py
from lib import *
Script:
import init
init.config = 'New'
init.run()
print init.config
Output:
Original
New
The function run() looks for config in lib.py, but print init.config looks for it in init.py. Thanks for the help everyone. Fix is to change the way the module installs (no init.py). Eventually, I hope to remove all the global variables, but for the time being everything works perfect.
What you describe would be inconsistent with how Python works (read, if you like, "I don't believe you did precisely that and got precisely that result").
If you go importing lib from different places or in different ways, though, you could be ending up with two copies of it, either two copies of one of the modules or one of the current-directory lib and the other the installed lib. If you are getting this "Original"/"New" behaviour, that seems to me the most likely reason.