[FIXED] Jupyter notebook not recognizing packages in venv

Issue

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

Solution

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.

Answered By - Ken