List: (a) pip installed packages that can be found on conda, (b) pip-only installed packages that are outdated.

compare_pip_and_conda_packages.py

#!/usr/bin/env python

import subprocess

print("Finding packages conda says are installed by pip...")
conda_raw = subprocess.run(
    ['conda', 'list'],
    stdout=subprocess.PIPE,
    stderr=subprocess.PIPE,
).stdout.decode('utf-8')

pip_only_pkgs = {
    ln.split(' ')[0]
    for ln in conda_raw.split('\n')
    if 'pypi' in ln
}


print("Finding packages pip says are outdated...")
pip_raw = subprocess.run(
    ['pip', 'list', '--outdated'],
    stdout=subprocess.PIPE,
    stderr=subprocess.PIPE,
).stdout.decode('utf-8')

pip_outdated_pkgs = {
    ln.split(' ')[0]
    for ln in pip_raw.split('\n')[2:-1]
}

# search conda for pip installed packages
on_conda = []
not_on_conda = []
not_on_conda_and_outdated = []

is_outdated_msg_lookup = {
    False: "but is up to date",
    True: "and is also outdated!"
}


print("Searching conda for pip installed packages...")
for pkg in pip_only_pkgs:

    search_raw = subprocess.run(
        ['conda', 'search', pkg],
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
    ).stdout.decode('utf-8')

    if "No match found for" in search_raw:
        not_on_conda.append(pkg)
        msg = "  - '{}' is not not conda... {}"
        outdated = pkg in pip_outdated_pkgs
        if outdated:
            not_on_conda_and_outdated.append(pkg)
        print(msg.format(pkg, is_outdated_msg_lookup[outdated]))
    else:
        on_conda.append(pkg)
        print(f"  - '{pkg}' is on conda!")

print()
print("Packages that seem to be pip only at the moment:")
print(" ".join(not_on_conda))
print()
print("Pip only packages that are outdated:")
print(" ".join(not_on_conda_and_outdated))
print()
print("Packages you could uninstall from pip and install on conda:")
print(" ".join(on_conda))