Virtual Environment Version Control Summary Python

Overview

Python is not compatible with 2 series and 3 series respectively. There are two versions on the market because of this relationship.

Because there was a slide that introduced the method of virtual environment management in an easy-to-understand manner I borrowed the contents of that slide and added the contents of the virtualenv that I mainly use. If you want to know more, please refer to the references.

pyenv-virtualenv can be set for each directory, and unlike vitalenv, it does not need to be activated at the time of use, so it is the most recommended.

Virtual environment introduction

virtualenv -A tool that allows you to switch between libraries used in the same version of Python. ・ Can be installed with pip ・ Can be used on Windows <Citation: [Machine Learning Nagoya_7th Study Group_Python Environment Construction Method.key](https://speakerd.s3.amazonaws.com/presentations/0d969d6526dd4b5fa0549f4e3481745f/%E6%A9%9F%E6%A2%B0 % E5% AD% A6% E7% BF% 92% E5% 90% 8D% E5% 8F% A4% E5% B1% 8B_% E7% AC% AC7% E5% 9B% 9E% E5% 8B% 89% E5 % BC% B7% E4% BC% 9A_Python% E7% 92% B0% E5% A2% 83% E6% A7% 8B% E7% AF% 89% E6% 96% B9% E6% B3% 95_20161015.pdf)> pyenv -Tools for managing various Python versions ・ You can switch between Python 2 and 3 -Python to be used in shell and directory can be specified -You cannot switch libraries with the same version of Python. ・ Cannot be used on Windows <Citation: [Machine Learning Nagoya_7th Study Group_Python Environment Construction Method.key](https://speakerd.s3.amazonaws.com/presentations/0d969d6526dd4b5fa0549f4e3481745f/%E6%A9%9F%E6%A2%B0 % E5% AD% A6% E7% BF% 92% E5% 90% 8D% E5% 8F% A4% E5% B1% 8B_% E7% AC% AC7% E5% 9B% 9E% E5% 8B% 89% E5 % BC% B7% E4% BC% 9A_Python% E7% 92% B0% E5% A2% 83% E6% A7% 8B% E7% AF% 89% E6% 96% B9% E6% B3% 95_20161015.pdf)> pyenv-virtualenv -A tool that allows you to switch libraries with the same version of Python with pyenv. ・ The author is the same as pyenv ・ Cannot be used on Windows <Citation: [Machine Learning Nagoya_7th Study Group_Python Environment Construction Method.key](https://speakerd.s3.amazonaws.com/presentations/0d969d6526dd4b5fa0549f4e3481745f/%E6%A9%9F%E6%A2%B0 % E5% AD% A6% E7% BF% 92% E5% 90% 8D% E5% 8F% A4% E5% B1% 8B_% E7% AC% AC7% E5% 9B% 9E% E5% 8B% 89% E5 % BC% B7% E4% BC% 9A_Python% E7% 92% B0% E5% A2% 83% E6% A7% 8B% E7% AF% 89% E6% 96% B9% E6% B3% 95_20161015.pdf)>

Installation / use

I've also introduced how to install Linux and Windows. Since the amount of sentences will be large, I will omit it only for Mac.

virtualenv

Installation

Installation

$ pip install virtualenv

Create virtual environment

$ virtualenv -p [Python version] [Virtual environment name]

#Example
$ virtualenv -p 3.5 python3.5

use

use

$ source [Virtual environment name]/bin/activate

#Example
source python3.5/bin/activate

If successful, the terminal display will be displayed.

(python3.5)$

 Should have changed.



#### **`End`**
```shell

$ deactivate

If you want to delete the environment, you can delete the created directory.

pyenv-virtualenv

Installation

Installation

$ brew install pyenv-virtualenv

Environment variable settings(For bash, the default is bash)

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

If you use a shell other than bash, please change the **. Bash_profile ** part.

Environment variable settings(For zsh)

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

Python installation

pyenv install [Python version]

Create virtual environment

$ pyenv virtualenv [Python version] [Virtual environment name]

#Example
$ pyenv virtualenv 2.7.11 Py2Base
$ pyenv virtualenv Py2Base py2-test 

If you create a new virtual environment from the virtual environment, it seems that the library etc. will be inherited.

use

Change Python used as standard

$ pyenv global [Virtual environment name]

Change Python in the current shell

$  pyenv shell [Virtual environment name]

Change Python in the current directory

$ pyenv local [Virtual environment name]

Delete virtual environment

$ pyenv unisntall [Virtual environment name]

References

[Machine learning Nagoya_7th study session_Python environment construction method.key](https://speakerd.s3.amazonaws.com/presentations/0d969d6526dd4b5fa0549f4e3481745f/%E6%A9%9F%E6%A2%B0%E5% AD% A6% E7% BF% 92% E5% 90% 8D% E5% 8F% A4% E5% B1% 8B_% E7% AC% AC7% E5% 9B% 9E% E5% 8B% 89% E5% BC% B7% E4% BC% 9A_Python% E7% 92% B0% E5% A2% 83% E6% A7% 8B% E7% AF% 89% E6% 96% B9% E6% B3% 95_20161015.pdf)