Python: Difference between revisions

Line 1:

~~== System-wide installation ==~~

The Python packages available to the interpreter must be declared when installing Python.

~~Supposing you want~~ Python 3 with <code>pandas</code> and <code>requests</code>, ~~then~~ <code>~~configuration.nix~~</code> ~~should then look something like~~

To install, say Python 3 with <code>pandas</code> and <code>requests</code>, define a new package <code>python-with-my-packages</code>:

~~environment.systemPackages =~~ let

with pkgs;

~~myPythonPackages~~ = ~~pythonPackages~~: with ~~pythonPackages~~; [

let

my-python-packages = python-packages: with python-packages; [

pandas

requests

# other python packages you want

];

in with ~~pkgs; [~~

python-with-my-packages = python3.withPackages my-python-packages

(python3.withPackages ~~myPythonPackages)~~

in ...

~~# all your other (non~~-~~Python)~~ packages

]

</syntaxhighlight>

You can put <code>python-with-my-packages</code> into your environment.systemPackages for a system-wide installation, for instance.

There are several versions of Python available. Replace <code>python3</code> with <code>python2</code> or <code>pypy</code> in the above snippet according to your needs.

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=== Explanation (optional) ===

We defined a function <code>~~myPythonPackages~~</code> which takes as input a set <code>~~pythonPackages~~</code> and returns a list of attributes thereof.

We defined a function <code>my-python-packages</code> which takes as input a set <code>python-packages</code> and returns a list of attributes thereof.

=== ~~Dealing with~~ missing/~~outdated~~ packages ===

== Using alternative packages ==

We saw above how to install Python packages using nixpkgs. Since these are written by hand by nixpkgs maintainers, it isn't uncommon for packages you want to be missing or out of date.

=== pip ===

Add <code>virtualenvwrapper</code> to your list of Python packages above. Pure Python packages can be installed in a virtualenv using pip. The package <code>pandas</code> in the example below won't work.

Put your packages in a requirements.txt:

pandas

requests

</syntaxhighlight>

Then setup the virtualenv:

virtualenv my-new-python-venv

source my-new-python-venv/bin/activate

pip install -r requirements.txt

</syntaxhighlight>

=== conda ===

Install the package <code>conda</code> and run

conda-shell

conda-env create --name my-new-conda-env -f requirements.txt

</syntaxhighlight>

~~Add <code>virtualenvwrapper</code> to your list of Python packages above. You can~~ use ~~pip safely inside such a virtualenv, most pure Python packages should work.~~

==== Imperative use ====

It is also possible to use <code>conda-install</code> directly.

~~$ virtualenv my-new-python~~-~~venv~~

On first use, run

~~$ source my-new-python~~-~~venv/bin/activate~~

~~$ pip~~ install ~~pandas_datareader # or some other package you want~~

conda-shell

conda-install

</syntaxhighlight>

to set up conda in <code>~/.conda</code>

~~This, of course, goes against the declarative nature of the rest of the configuration and should be avoided if possible.~~

=== pypi2nix ===

== Contribution guidelines ==

@@ Line 1: / Line 1: @@
-== System-wide installation ==
 The Python packages available to the interpreter must be declared when installing Python.
-Supposing you want Python 3 with <code>pandas</code> and <code>requests</code>, then <code>configuration.nix</code> should then look something like
+To install, say Python 3 with <code>pandas</code> and <code>requests</code>, define a new package <code>python-with-my-packages</code>:
 <syntaxhighlight lang="nix">
-environment.systemPackages = let
+with pkgs;
-   myPythonPackages = pythonPackages: with pythonPackages; [
+let
+   my-python-packages = python-packages: with python-packages; [
      pandas
      requests
      # other python packages you want
    ];
-in with pkgs; [
+  python-with-my-packages = python3.withPackages my-python-packages
-  (python3.withPackages myPythonPackages)
+in ...
-  # all your other (non-Python) packages
-]
 </syntaxhighlight>
+You can put <code>python-with-my-packages</code> into your environment.systemPackages for a system-wide installation, for instance.
 There are several versions of Python available. Replace <code>python3</code> with <code>python2</code> or <code>pypy</code> in the above snippet according to your needs.
@@ Line 22: / Line 20: @@
 === Explanation (optional) ===
-We defined a function <code>myPythonPackages</code> which takes as input a set <code>pythonPackages</code> and returns a list of attributes thereof.
+We defined a function <code>my-python-packages</code> which takes as input a set <code>python-packages</code> and returns a list of attributes thereof.
-=== Dealing with missing/outdated packages ===
+== Using alternative packages ==
+We saw above how to install Python packages using nixpkgs. Since these are written by hand by nixpkgs maintainers, it isn't uncommon for packages you want to be missing or out of date.
+=== pip ===
+Add <code>virtualenvwrapper</code> to your list of Python packages above. Pure Python packages can be installed in a virtualenv using pip. The package <code>pandas</code> in the example below won't work.
+Put your packages in a requirements.txt:
+<syntaxhighlight>
+pandas
+requests
+</syntaxhighlight>
+Then setup the virtualenv:
+<syntaxhighlight lang="shell">
+virtualenv my-new-python-venv
+source my-new-python-venv/bin/activate
+pip install -r requirements.txt
+</syntaxhighlight>
+=== conda ===
+Install the package <code>conda</code> and run
+<syntaxhighlight lang="shell">
+conda-shell
+conda-env create --name my-new-conda-env -f requirements.txt
+</syntaxhighlight>
-Add <code>virtualenvwrapper</code> to your list of Python packages above. You can use pip safely inside such a virtualenv, most pure Python packages should work.
+==== Imperative use ====
-<syntaxhighlight lang="console">
+It is also possible to use <code>conda-install</code> directly.
-$ virtualenv my-new-python-venv
+On first use, run
-$ source my-new-python-venv/bin/activate
+<syntaxhighlight lang="shell">
-$ pip install pandas_datareader # or some other package you want
+conda-shell
+conda-install
 </syntaxhighlight>
+to set up conda in <code>~/.conda</code>
-This, of course, goes against the declarative nature of the rest of the configuration and should be avoided if possible.
+=== pypi2nix ===
 == Contribution guidelines ==