Answers for "pip install opencv-python fails"

python install opencv

#Basic package
pip install opencv-python
#Full package
pip install opencv-contrib-python

python install opencv

# install any one of them to avoid conflicts
# I prefer 2nd one
pip install opencv-python
pip install opencv-contrib-python

# for linux, you may have two python version on your pc
# so - 
pip3 install opencv-contrib-python