Building a Python environment on Mac

Since I did a clean installation of Mac, I will write about building a Python development environment.

Installation of pyenv and virtualenv

Installed using Homebrew.

$ brew install pyenv-virtualenv

After the installation is complete, follow the instructions of homebrew and add the following line to the configuration file of your shell (~ / .bashrc for bash, ~ / .zshrc for zsh).

$ export PYENV_ROOT=/usr/local/var/pyenv
$ if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi
$ if which pyenv-virtualenv-init > /dev/null; then eval "$(pyenv virtualenv-init -)"; fi

After saving, load the configuration file.

$ source ~ / .bashrc # for bash $ source ~ / .zshrc # for zsh

Install Python3

You can see which versions of Python you can install with pyenv install --list.

This time I will install the latest 3.5.1 at the moment.

$ pyenv install 3.5.1

However, the build failed here. After investigating, it seems that Xcode command line tools should be installed. So install it with the following command.

$ xcode-select --install

When I installed it with pyenv again, it was installed properly. Installation is complete when the following is displayed.

Downloading Python-3.5.1.tgz...
-> https://www.python.org/ftp/python/3.5.1/	Python-3.5.1.tgz
Installing Python-3.5.1...
Installed Python-3.5.1 to /usr/local/var/pyenv/	versions/3.5.1

Check if it is installed just in case.

$ pyenv versions

I got the following output and it seems that I was able to install it properly.

* system (set by /usr/local/var/pyenv/version)
  3.5.1

I want to use the 3 series as the main, so I also set it.

$ pyenv global 3.5.1
$ pyenv versions
  system
* 3.5.1 (set by /usr/local/var/pyenv/version)

This has changed. If there is a * on the left side, the setting is complete.

(Addition) Even though I set it to 3.5.1 with pyenv global, for some reason, when I look at the version with python --version, it is Python that comes with the Mac standard.

$ python --version
Python 2.7.5

Reloading the shell config file will result in the version set in pyenv.

$ source ~/.zshrc
$ python --version
Python 3.5.1

Probably because of my environment, I'm investigating the cause. If you comment out ʻif which pyenv> / dev / null; then eval "$ (pyenv init-)"; fidescribed in~ / .zshrc, the Python version changes even if source ~ / .zshrc` I don't have it, so I think this area is probably suspicious.

(Additional notes) solved. The order of the lines described in ~ / .zshrc was just changed ... I was shocked to take time for such a simple thing.

It was like this (the setting for $ PYENV_ROOT came after ʻeval" $ (pyenv init-) "`).

$ if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi
$ export PYENV_ROOT=/usr/local/var/pyenv
$ if which pyenv-virtualenv-init > /dev/null; then eval "$(pyenv virtualenv-init -)"; fi

Solved by swapping the first and second lines of this.

$ export PYENV_ROOT=/usr/local/var/pyenv
$ if which pyenv > /dev/null; then eval "$(pyenv init -)"; fi
$ if which pyenv-virtualenv-init > /dev/null; then eval "$(pyenv virtualenv-init -)"; fi

I don't think there are many people who make such mistakes, but I wrote it down just in case.

Creating a virtual environment with virtualenv

By setting pyenv virtualenv [version] [name], you can create a virtual environment named name with the Python version version.

$ pyenv virtualenv 3.5.1 test_351

You have now created a virtual environment named test_351. You can check it with pyenv versions.

$ pyenv versions
  system
* 3.5.1 (set by /usr/local/var/pyenv/version)
  3.5.1/envs/test_351
  test_351

After that, go to the folder used for development and set the virtual environment created earlier.

$ cd dev
$ pyenv local test_351

By doing this, from now on, when you go to the dev folder, you will automatically be in the environment of test_351.

If you want to delete the virtual environment, see below.

$ pyenv uninstall [name]

Finally

It seems that it will be more convenient if you use a wheel, but I will do it again this time.