What Is pip? Install and Troubleshoot Python Packages

pip installs Python distributions into a particular Python environment. Run it through that interpreter with python -m pip so you can see where packages are going. A successful installation in one environment does not make the package available to every Python process on your computer.

pip, Python, and PyPI are different things

Python runs your program. pip installs distributions such as packaging. PyPI is a package index that pip commonly uses. A distribution name is not always its import name: consult the package documentation instead of guessing a similar-looking package.

Start with an isolated environment

In a new practice directory on macOS or Linux, run the following commands. They create a directory named .venv and install only into that environment. Choose the Python version your project supports.

python3 -m venv .venv
.venv/bin/python -m pip --version
.venv/bin/python -m pip install "packaging==26.3"
.venv/bin/python -m pip show packaging
.venv/bin/python -m pip check

In Windows PowerShell, use these equivalent commands. Calling the environment interpreter directly avoids changing PowerShell execution policy just to activate it.

py -m venv .venv
.venv\Scripts\python.exe -m pip --version
.venv\Scripts\python.exe -m pip install "packaging==26.3"
.venv\Scripts\python.exe -m pip show packaging
.venv\Scripts\python.exe -m pip check

The version above is a reproducible teaching pin, not a promise to be the newest release. The pip path and package location should be inside .venv. With compatible installed requirements, pip check reports No broken requirements found. It checks dependency compatibility, not security or application behavior. The Python Packaging guide explains environment creation and installation.

Prove that the importing interpreter is the one you installed into

import sys
from importlib.metadata import version
from packaging.version import Version

print(sys.executable)
print(version("packaging"))
assert Version("2.10") > Version("2.9")
print("Version comparison passed.")

Save this as check_package.py and run it with the same environment interpreter. Expect version 26.3 and the final success message. If an IDE or notebook still cannot import the package, select this interpreter or kernel there. Reinstalling into a different terminal environment will not fix that mismatch.

Find packages without pip search

Use the PyPI website and the package maintainer's installation documentation to find a package. PyPI no longer supports the search endpoint used by pip search; that command is not a working PyPI discovery workflow. See the pip search documentation. Verify the exact project name, supported Python versions, source repository, and release history before installing it.

Record a small dependency file

Create requirements.txt containing the following line, then install it with python -m pip install -r requirements.txt using your environment interpreter.

packaging==26.3

python -m pip freeze records installed distributions, including transitive dependencies; it does not establish that your environment is minimal, secure, or portable. Check the resulting file before using it as a project dependency list. Versions, Python version, platform, and native libraries all affect reproducibility. For stronger reproducible builds, see pip's repeatable-install guidance.

Troubleshoot the actual failure

Upgrade deliberately and test

Change one dependency constraint in an isolated environment, run pip check, then run your application's tests. A successful resolver or import is not proof that behavior is unchanged. Keep the previous dependency file so you can recreate the earlier environment rather than trying to repair a shared installation by trial and error.

Next steps and validation scope

The commands and import example were checked in a fresh macOS Python 3.12.14 environment with packaging 26.3. The Windows commands were reviewed against the packaging documentation but were not executed on Windows. For environment selection problems, see PATH and interpreter diagnostics. For the exact compatibility-check contract, see pip check.