Jupyter notebook not recognizing packages in venv [duplicate]

Question

This has been driving me crazy. For some reason it seems like my .ipynb file doesn't recognize the python packages in my venv. I get this error even though I've clearly installed opencv. I run into this exact same problem for dlib and imutils too.

However, when I use opevcv in a regular .py file in the save venv, it works completely fine so it's something to do with .ipynb (Jupiter Notebooks).

I have tried pip3 install opencv-python

Note: I am pretty sure I have selected the correct venv when running my .ipynb file.

The output I get when I run !pip list in the Jupyter Notebook (which includes opencv-python):

Package                 Version
----------------------- -------------------
absl-py                 0.12.0
astunparse              1.6.3
cachetools              4.2.1
certifi                 2020.12.5
chardet                 4.0.0
cmake                   3.18.4.post1
cycler                  0.10.0
dlib                    19.22.0
flatbuffers             1.12
gast                    0.4.0
google-auth             1.29.0
google-auth-oauthlib    0.4.4
google-pasta            0.2.0
grpcio                  1.34.1
h5py                    3.1.0
idna                    2.10
imutils                 0.5.4
keras-nightly           2.5.0.dev2021032900
Keras-Preprocessing     1.1.2
kiwisolver              1.3.1
Markdown                3.3.4
matplotlib              3.4.1
numpy                   1.19.5
oauthlib                3.1.0
opencv-python           4.5.1.48
opt-einsum              3.3.0
Pillow                  8.2.0
pip                     21.0.1
protobuf                3.15.8
pyasn1                  0.4.8
pyasn1-modules          0.2.8
pyparsing               2.4.7
python-dateutil         2.8.1
requests                2.25.1
requests-oauthlib       1.3.0
rsa                     4.7.2
setuptools              54.1.2
six                     1.15.0
tensorboard             2.5.0
tensorboard-data-server 0.6.0
tensorboard-plugin-wit  1.8.0
tensorflow              2.5.0rc1
tensorflow-estimator    2.5.0rc0
termcolor               1.1.0
typing-extensions       3.7.4.3
urllib3                 1.26.4
Werkzeug                1.0.1
wheel                   0.36.2
wrapt                   1.12.1

Please help, thank you

Answer 1

Are you using your local machine? How do you fire up the jupyter notebook? You could try the following:

1. Open a prompt and activate your virtual environment.
2. python And then >>> import <module>: Does it import it?

Make sure that you have jupyter insatlled in that environment and then

1. Open a prompt and activate your virtual environment.
2. Issue python -m jupyter notebook

Answer 2

Maybe this question will be deleted but this is what fixed it for me (thanks to @Shi XiuFeng):

I had initially created my venv with virtualenv env which didn't work, and so when I recreated the venv with python3 -m venv env this worked completely fine.