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| − | == Check Python ==
| + | Hynek Schlawack |
| − | Check the version of the default Python interpreter:
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| − | <code>python --version</code>
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| − | List the versions of python available:
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| − | <code>ls /usr/bin/python*</code>
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| − | Use <code>update-alternatives</code> to setup system-wide ability to choose Python interpreter. The one with the '''higher''' priority number will become the default.<br>
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| − | <code>update-alternatives --install /usr/bin/python python /usr/bin/python2.7 1</code><br>
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| − | <code>update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2</code>
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| − | Now we can list the choices:
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| − | <code>update-alternatives --list python</code>
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| − | And choose one:
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| − | <code>update-alternatives --config python</code>
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| − | We can also remove a choice if it's no longer an option on the system:
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| − | <code>update-alternatives --remove python /usr/bin/python2.7</code>
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| − | == Python Virtual Environments ==
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| − | See Digital Ocean's quick guide to [https://www.digitalocean.com/community/tutorials/how-to-install-python-3-and-set-up-a-local-programming-environment-on-ubuntu-16-04 setting up a local Python programming environment], including [https://virtualenv.pypa.io/en/stable/ virtual environments], which is what I did for [https://github.com/Miserlou/SoundScrape SoundScrape] Btw, SoundScrape is a neat tool to download sound files from SoundCloud.
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| − | <ref>
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| − | <source lang="bash">
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| − | cd
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| − | mkdir environments
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| − | cd environments/
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| − | pyvenv my_env
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| − | source my_env/bin/activate
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| − | pip install --upgrade pip
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| − | pip install soundscrape
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| − | pip install soundscrape --upgrade
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| − | soundscrape https://soundcloud.com/pianoman_weddings/coldplay
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| − | </source>
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| − | </ref>
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| − | Hynek Schlawack (from 2013) | |
| | * [https://hynek.me/talks/python-deployments/ Notes] | | * [https://hynek.me/talks/python-deployments/ Notes] |
| | * [https://www.youtube.com/watch?v=RvbDCzroavY Video] | | * [https://www.youtube.com/watch?v=RvbDCzroavY Video] |
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| − | == Python Packaging ==
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| − | In the old days (2015) there were still debates about how to package Python and install stuff. Now, it's settled. Use pip. Easy_install is dead. See the [https://docs.python.org/3/installing/index.html docs]. Also note that <code>venv</code> is the successor to <code>virtualenv</code>
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| − | == Basic PIP and Virtual Environments ==
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| − | Do NOT (normally) use sudo with pip. Use a virtual environment. As of Python 3.4, the command is now called <code>pyvenv</code> or simply <code>venv</code>. As of Python 3.6 <code>pyvenv</code> is '''deprecated''' in favor of using <code>python3 -m venv</code> to help prevent any potential confusion as to which Python interpreter a virtual environment will be based on. '''python3''' is not generic. It represents the '''exact''' version you wish to use in your virtual environment.
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| − | As an example, I needed to create a Python Virtual Environment to use the [https://github.com/freephile/meza/issues/63#issuecomment-2020431602 Ansible Playbook Grapher]
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| − | <source lang="bash">
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| − | python3.11 -m venv myenv
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| − | # .. some output ..
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| − | source myenv/bin/activate
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| − | # maybe upgrade pip
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| − | pip install --upgrade pip
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| − | # then install your local environment packages
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| − | pip install what-i-want
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| − | # done using this python?
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| − | deactivate
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| − | </source>
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| − | You only use sudo or elevated permissions when you want to install stuff for the global, system-wide Python installation.
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| − | It is best to use a virtual environment which isolates packages for you. That way you can play around without polluting the global python install.
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| − | As a bonus, virtualenv does not need elevated permissions.
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| − | * Installing a package is as simple as <code>pip install foo</code>
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| − | * Upgrades are <code>pip install --upgrade foo</code>
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| − | * <code>pip uninstall foo</code> if you want to remove foo
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| − | {{References}}
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| − | [[Category:Python]]
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| − | [[Category:System Administration]]
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| − | [[Category:Programming]]
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| − | [[Category:DevOps]]
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