I want to completely reinstall Python 2 but none of the guides I have found allow me to uninstall it. No matter what I do, python --version still returns 2.7.10, even after I run the Python 2.7.11 installer. All the other guides on StackOverflow tell me to remove a bunch of files, but python is still there.
This may be a bit late, but for future searchers I'll post anyway:
I was looking to do the same. But I came across this paragraph at the Foundation (Getting and uninstalling MacPython) which convinced me to leave well alone and not uninstall it.
The Apple-provided build of Python is installed in /System/Library/Frameworks/Python.framework and /usr/bin/python, respectively. You should never modify or delete these, as they are Apple-controlled and are used by Apple- or third-party software. Remember that if you choose to install a newer Python version from python.org, you will have two different but functional Python installations on your computer, so it will be important that your paths and usages are consistent with what you want to do.
Set your an alias to use the python version that you want to use from inside your .bashrc (or zsh if you use it).
Like:
alias python='/usr/bin/python3.4'
Agree with the accepted answer that uninstalling is a bad idea, but for those of you using HomeBrew to install your own Python, you don't need an alias as in #Mat Marsiglio's answer. Rather you can do what the HomeBrew installation suggestions:
export PATH="/usr/local/opt/python/libexec/bin:$PATH"
This gives brew's python precedence over the built-in one at /usr/bin/python
Related
I've installed anaconda, but I still want to use python as normal within a Terminal window (zsh). At the moment, running which python shows /Users/USERNAME/opt/anaconda3/bin/python.
I don't want this command to point to my anaconda installation. I want to use python as I have in the past, and for it to point to my python 2.7 installation (/usr/bin/python).
The same issue is present with pip and with python3. How do I change these paths back to their default locations?
I want to start out by saying I personally have never used Anaconda, but I have many friends who have and they always seem to wind up getting into hot water as far as configurations go. If you don't need the data-science specific tools that Anaconda offers (most of which I imagine you can get just as easily by using pip install <package_name>), then I STRONGLY urge you to not use Anaconda. I would suggest you instead use homebrew to install python 3.7 and leave the system version of python 2.7 alone... Anyways...
I recently fixed an issue similar to the one you're describing for a friend. I ended up deleted his anacaonda build and reinstalling fresh from homebrew (link: https://brew.sh/), so this is how I helped him and hopefully this will help you too.
Firstly, I would check the configuration of your ~/.bash_profile (or potentially ~/.bashrc) file. Comment out any lines you find that have to do with Anaconda by preceding with the # character. I believe when anaconda installs it puts the location of the anaconda-version-of-python higher in the PATH hierarchy, therefore you computer sees it first before it has the chance to look in /usr/bin...
Secondly, you need to move the anaconda-python to the trash... I would start by trashing the whole '/Users/USERNAME/opt/anaconda3' directory. If memory serves me correctly anaconda stores other python related things in the /MacitoshHD/Library/Frameworks directory, but don't quote me on that. I would advise looking there and trashing whatever seems to be related to the anaconda install.
After that, in a new terminal (so that your PATH refreshes), I installed homebrew, and then ran the command brew install python3 to install python3. I think perhaps I ran the command recommended in the installer output, something like "brew link python3" to symlink python3 where it needs to be linked after the installation.
Finally, everything is done python2 and python3 are installed and working with no issues. python2 is the system default version and python3 is the homebrew installed version. Feel free to ask any questions and I will try to help more, hopefully those instructions will get you started though.
I've installed python 2x and 3x with Homebrew at /usr/local/Cellar/, and again with pydev at ~/.pyenv for both versions. Also installed with .dmg for both. I can't decide which is nicer to work on. Please advice me.
And I'd like to remove some. Which of these would be unnecessary and can be removed?
don't delete files on /usr/bin, if you want to remove some python, like python2: brew uninstall python2.
The pyenv is a very good tool. I'm use it betw on py2 or py3 very well.
And there is another good tool for python dev：virtualenv
Supposedly Python 2.7 is included native to OSX 10.8 and above (if I remember correctly), but I recently installed Python 3.5 to use for projects while I work through UDacity. Lo and behold, the UDacity courses seem to use 2.7 - wups! So instead of trying to uninstall 3.5 (this procedure seemed to scary for neophytes such as myself), I simply installed 2.7 in addition to the recently installed 3.5 and just run the 2.7 IDLE and Shell. Is this ok, or will I run into problems down the road?
I have installed two versions, 2.7, 3.4 and I do not have any problem by now. 3.4 I am using for my work project in eclipse environment, 2.7 for udacity course, like You ;).
As long as you keep your installation folders organized, you should have no issues having both on your computer, besides one thing. The path environment variable for python will determine which version is used by default, so I would say stick to one version, or make sure to make your programs as backwards compatible as possible. I have run into this issue on Windows, since I installed Python 3.4 before 2.7, and therefore to run older code, I have to manually select the python executable. In terms of libraries, I believe that for each python version, the libraries are completely separate, so you should be good there.
As others have said, if the installation directory is different it should be no problem at all.
One thing that'll make your life easier for switching between the two is to use an IDE such as PyCharm, you just have to change a drop down to switch between the two versions.
It should be fine. Its actually pretty common to have multiple Python environments. It helps to prevent dependency conflicts between your projects. That is what is happening when you are using tools like pyenv and virtualenv.
Using tools like pyenv and virtualenv may also help you with the path problems that others mentioned. They have commands to set up the path so that their version of pip, python, etc are used.
Im not sure about OSX, but with windows 10 my environment variables for 2.7 were overwritten with the 3.5 path. Not a tough fix, but a little confusing, since it was months later when I needed 2.7 again.
You can also use Anaconda for maintaining two versions of Python:
Download Anaconda for both Python versions
Open .bashrc
Add the path to new Anaconda you have installed for, e.g.:
export PATH="/home/paras/anaconda3/bin:$PATH"
Now there will be 2 export paths: one for Python 2 and one for Python 3. Comment the one which you don't want.
I have the same problem and it is not necessary to uninstall on version of python. Please take care to not mix them up - When you search them up on the start menu. You can make a desktop shortcut saying 2.6 and 3.5.
If I install several packages with Python 2.6 (e.g. using easy_install) and then I want to upgrade to Python 2.7, is there a way to upgrade Python and then automatically "import" all those installed packages along with it? Or do they have to be reinstalled?
Two related questions: (1) if a package is installed in a Python 2.6 packages directory, is it legitimate to import it into the PYTHONPATH of a newer Python, like Python 2.7, or must all the packages be reinstalled with Python 2.7? (2) if I use easy_install, how can I tell it to use the newer Python? E.g. 2.7 instead of 2.6? Or should I just reinstall easy_install using Python 2.7 to do this? thanks.
First, this is one of the many reasons you want to use pip instead of easy_install. (You still need easy_install to get pip itself, but beyond that, don't touch it ever again.) If you'd used pip, you could just do this:
pip freeze > modules.dump
That gives you a list of all of the modules you have installed, and their version numbers. Most of the time, you can just take the list of modules (line.split('==')[0] for line in f) and pass it to pip install.
But that's for future reference. For today, you have to piece it together yourself by looking through your site-packages directory. Fortunately, many things will end up as foo_bar-1.2.3.4-blah-blah.egg, so all you have to do is guess whether the package is named foo-bar or foo_bar at PyPI, and usually even if you guess wrong, easy_install or pip will get the right thing anyway. So, you can't quite automate it, but you can get close.
But yes, however you do it, you do need to reinstall. Anything that requires C extension code has to be recompiled. Pure-Python packages may not need to be changed, but they may, and you're better safe than sorry. Also, if you try to copy some things over but not others, you're going to make a big mess of your dependencies.
(1) if a package is installed in a Python 2.6 packages directory, is it legitimate to import it into the PYTHONPATH of a newer Python, like Python 2.7, or must all the packages be reinstalled with Python 2.7?
Don't do that; reinstall them, as explained above.
(2) if I use easy_install, how can I tell it to use the newer Python? E.g. 2.7 instead of 2.6? Or should I just reinstall easy_install using Python 2.7 to do this? thanks.
You need the 2.7 easy_install. You can usually use a 2.7 easy_install with 2.6 by running, e.g., python2.6 $(which easy_install), but the other way around isn't guaranteed to work.
And you don't want to do that anyway. If you want two versions of Python in parallel, you want two versions of easy_install—normally you want to end up with easy_install-2.6 and easy_install-2.7, with easy_install as a symlink to whichever one you consider your "primary" python.
I new to Python and to programming in general. I'm a novice, and do not work in programming, just trying to teach myself how to program as a hobby. Prior to Python, I worked with Ruby for a bit and I learned that one of the biggest challenges was actually properly setting up my computer.
Background: I'm on a Macbook with OSX 10.7.
With Ruby, you have to (or rather, you should), edit your ./profile and add PATH info. When you install and use RVM, there are additional items you need to add to your bash_profile.
Do you have to make similar changes with Python? What are the best practices as I'm installing/getting started to ensure I can install modules and packages correctly?
python works out of the box on OS X (as does ruby, for that matter). The only changes I would recommend for a beginner are:
1) Python likes to be reassured that the terminal can handle UTF-8 before it will print Unicode strings. Add export LANG=en_US.UTF-8 to .profile. (It may be that the .UTF-8 part is already present by default on Lion - I haven't checked since Snow Leopard.) Of course, this is something that will help you in debugging, but you shouldn't rely on it being set this way on other machines.
2) Install pip by doing easy_install pip (add sudo if necessary). After that, install Python packages using pip install; this way, you can easily remove them using pip uninstall.
Take a loot at Python on the Macintosh page first. Like it says, Python comes pre-installed on Mac OS X. It means that you don't have to do anything special in order to use it.
To get started, you can run a Terminal.app, type python and that will get you Python interactive shell up and running.
However, Python on OS X might be of a slightly older version. For example, OS X 10.7.3 comes with Python 2.7.1, whereas latest release version of the Python is 3.2.3. If you want to use other versions, then you will have to install them. Then it all depends on what, where and how you install. If you want to have multiple versions alongside, you may need to set some environment variables like PATH to have binaries you installed found by the bash etc. You can do it through bash ~/.profile if needed.
But until you get to that point - don't worry about it use a version shipped with OS X. Once you want a newer one - download and install it. Then, if it doesn't work out of the box or you have any other problems or concerns, feel free to ask a more specific question.