Texas A&M University (TAMU) ENGR102 Engineering Lab I - Computation Practice Exam

The installation of external Python libraries is most commonly accomplished using 'pip', which is the package manager for Python. Pip enables users to easily download and install packages from the Python Package Index (PyPI) directly from the command line. It simplifies the management of libraries and dependencies, making it straightforward to add new tools and packages to a Python environment.

When you want to use a library that is not part of the standard library, you can quickly install it using a command like `pip install package_name`, which makes it a preferred method among developers. This approach also allows for package upgrades and uninstalls, making it very versatile.

The other methods mentioned do have their uses, but they are not as universally convenient or widely used for installing libraries. For instance, while you can access the package manager features through the Python interpreter, it is not as direct and user-friendly as using pip in the command line. Similarly, using a setup.py file is often specific to certain packages that require a custom installation procedure, but this method does not provide the ease of use that pip does.