Ubuntu doesn't ship with pip or virtualenv. In fact it ships with a version of Python where the built-in equivalent to virtualenv, pyvenv, is explicitly disabled.
So you have to install extra Python packages, as root. You have to have that Python experience that guides you to install as few of them as you can, just enough so you can get started with a virtualenv, so you don't end up relying on your system Python environment.
And this is really hard to explain to people who aren't deeply familiar with Python. "Never use sudo to install Python packages! Oh, you got errors. We obviously meant use sudo for two particular packages and never again after that."
In the terrible case where you don't have root, you have to ignore Ubuntu's version of Python and compile it yourself from scratch. Hope the right development libraries are installed!
Maybe I'm wrong and there's a method I've overlooked. If there is: please show me how to install a Python package on a fresh installation of Ubuntu 16.04, without ever using sudo, and I will happily spread the good news.
That sounds like a major problem with Ubuntu, rather than with Python or pip.
On Windows, meanwhile, the standard Python installer gets all this set up properly in like three clicks. Better yet, because it installs per-user by default, "pip install" just works. And if you still choose to install it globally, it will fail, but it will tell you exactly what you need to do to make it work:
Could not install packages due to an EnvironmentError: [WinError 5] Access is denied: ...
Consider using the `--user` option or check the permissions.
One can't help but wonder how we ended up in a situation where the most popular Linux distro somehow does Python worse than Windows.
Don't despair, in the Anaconda installed with visual studio (now a default) you can't update or install packages without being admin! And if you install Anaconda again it merges the start menu entries and you can't tell which is which...
Eh, that has always been the case for windows vs linux, that you don't have to compile anything yourself because there is always an installer that will deploy precompiled binaries for whatever you want to install (except for when there isn't, because nobody has compiled it for windows, at which point you're in deeper shit) (or except when something installs itself but doesn't update your envars, so you have to do it yourself, which kind of defeats the purpose of the whole "installer" thing).
Iiish. For small projects or when you want to get development versions etc that are not in a distro's repos it's pretty common to have to do a make-configure.
Then again, with Python in particular, I have often had errors either with pip-install, or after "successful" installation, for various reasons.
In this case, we were talking about Python itself. I don't see any particular reason why most people should need to build it themselves, whether on Windows or on Linux. Packages are another matter, but here the issue is the way Python itself is packaged on Ubuntu.
So you have to install extra Python packages, as root. You have to have that Python experience that guides you to install as few of them as you can, just enough so you can get started with a virtualenv, so you don't end up relying on your system Python environment.
And this is really hard to explain to people who aren't deeply familiar with Python. "Never use sudo to install Python packages! Oh, you got errors. We obviously meant use sudo for two particular packages and never again after that."
In the terrible case where you don't have root, you have to ignore Ubuntu's version of Python and compile it yourself from scratch. Hope the right development libraries are installed!
Maybe I'm wrong and there's a method I've overlooked. If there is: please show me how to install a Python package on a fresh installation of Ubuntu 16.04, without ever using sudo, and I will happily spread the good news.