how to check a python package is installed in ubuntu code example

Example 1: list all packages installed with pip

pipenv lock -r

Example 2: bash check if python package is installed

$ python2 -m doesnt_exist |& grep -q 'No module named' && echo 'Nope' || echo 'Yup'
Nope

$ python2 -m math |& grep -q 'No module named' && echo 'Nope' || echo 'Yup'
Yup