Python ModuleNotFoundError although module is installed [aiohttp]

Programming Help and Discussion
#1

hi there, im new to all this and been trying to get as far as i can by myself but ran into a wall that got me stuck.

i installed aiohttp using

pip install aiohttp

also, before trying to run my script i used

pip install -r requirements.txt

and got the ‘already satisfied’ result, but i still get the error msg

ModuleNotFoundError: No module named 'aiohttp'

i noticed similar questions were posted in the past but the replies seem to be specific to the scripts\modules the posts were referring to, and not to aiohttp so i did not find an answer to my problem (or did not manage to understand it).

id love some tips. this is the script im using: https://github.com/J3Patel/linkedin-learning-video-downloader

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#2

Did you check your PYTHONPATH value? Can aiohttp be found on that path? 

Python 2 or 3 ?

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#3

i’m not sure how to find that out.

i know i have python in path and when i check sys.path i see the libraries but i dont know what to conclude from that. how do i check if aiohttp can be found on that path?

im using python3.7

#4

i know i have python in path and when i check sys.path i see the libraries

Um. Sounds like you know more python than I do!

PYTHONPATH and PYTHONHOME are environment variables. I.e. things you check in terminal or command prompt (depending on whether you are using Linux/OSX or Windows, respectively). In a Windows command prompt you would type ‘set’ and look for the value of PYTHONPATH. It might not exist.

(Windows) If I do a “pip install”, the package is installed in “lib\site-packages” under the python folder. If I “print (sys.path)”, I see “lib\site-packages” as one of the entries, and I can expect “import <package>” to work.  If I run “python -S” and “print (sys.path)”, then “lib\site-packages” is NOT listed, and import will fail.

If python is not finding aiohttp, then it might be installed somewhere unexpected. You should be able to use PYTHONPATH to point that path, and sys.path will be updated accordingly when you next run python.

I’ve been bitten in the past when I have both python2 and python3 installed. In that case, I type “python3” to start python 3.x, and have to use “pip3” to install libraries for python 3.x.

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#5

Make sure that you are installing the packages and running the script as the same user. If on linux, and you are running the script with

sudo python script.py

you’ll need to install the package to root with

sudo pip install aiohttp
#6

gva-mobilion is right. The reason is that if you install a module into (say) Python 3.7.3 as user pi, it will go into /home/pi/.local/lib/python3.7/site-packages/. This directory is not in the search path of user root. You can either fix this permanently by re-installing as root, or temporarily by adding that directory to root’s search path.

To see the difference in paths, do:

% python3
>>> import sys
>>> print(sys.path)

% sudo python3
>>> import sys
>>> print(sys.path)