Popular recipes tagged "enum"

First Class Enums in Python (Python)

2013-03-07T13:10:29-08:00

Python recipe 578485 by James Mills (enum, immutable).

True immutable symbolic enumeration with qualified value access.

A simple enum type (Python)

2013-02-13T06:53:38-08:00

Python recipe 578455 by Eric Snow (enum, metaclass). Revision 2.

Inspired by various threads[1] on the python-ideas list, here's a simple enum type. Enums are generated either via the class syntax or via Enum.make().

class Breakfast(Enum):
    SPAM, HAM, EGGS
    BACON, SAUSAGE

Breakfast = Enum.make("SPAM HAM EGGS BACON SAUSAGE")

Here are some of the features:

Enum:

inheriting from an enum inherits copies of its values.
the export() method allows for exposing an enum's values in another namespace.

Enum Values:

the underlying values within an enum are essentially useless, diminishing the temptation to rely on them.
identity is equality, like with None, True, and False.
enum values support bitwise operations within the same enum.
the result of a bitwise operation is always the same object given the same inputs.

[1] see http://mail.python.org/pipermail/python-ideas/2013-January/019003.html

C-style enumerations (Python)

2013-01-29T16:13:39-08:00

Python recipe 578438 by Arthur Gardiner (enum, enumeration).

Fast and dirty C style enumerations specifically made for machine states but easily adapted. Not the most optimized implementation but a hardy read-only structure that I got tired of emailing around.

Python Immutable Enumerations Using Duck Punching (Python)

2012-10-18T19:41:22-07:00

Python recipe 578294 by Josh Friend (duckpunching, enum, enumeration, monkeypatching, python).

Here's a fun method of creating enumerations in Python using dynamic class creation and duck-punching (monkey-patching). It works by creating a class called enum using the type metaclass. Duck-punching is then used to add properties to the class. the fget method of the property returns the enum value, but the fset and fdel methods throw exceptions, keeping the enumeration immutable. You can have enum values assigned automatically in sequence, assign them yourself, or have a mix of both.

Simple enum mechanism (Python)

2012-01-15T12:30:31-08:00

Python recipe 578015 by Thomas Lehmann (enum).

Here are the basic ideas (orientation: C++):

You are responsible to find names for constants and this code provides a way to give values which differ from each other
The context is to allow different enums with values starting by 0
If you like to use constants like here: "Orientation.TOP" then place those constants in the relating class
You still can assign your own values

About the code:

It's not much code also it might look like (implementation + documentation + unittests)
The __docformat__ is for epydoc. Temporarily remove the "@singleton" when trying to generate the HTML documentation (can not yet be handled by epydoc).

Example(s): Have a look at the unittests please.

Python Enum and/or named-integer class (Python)

2011-11-29T10:04:41-08:00

Python recipe 577921 by Graham Poulter (enum). Revision 6.

Recipe for Python Enum class that builds on the "FOO = 1" pattern by adding a printable name.

In other words, an Enum instance is a named integer.

Yet another 'enum' for Python (Python)

2010-01-28T18:23:11-08:00

Python recipe 577024 by Gabriel Genellina (enum). Revision 5.

There are quite a few 'enum' recipes already here. This one is short, cheap, and has neither bells nor whistles :)

Yet again, one more enum for Python (Python)

2010-02-22T22:53:42-08:00

Python recipe 577063 by Anand (enum).

This is a fork of recipe #577024 which describes an enum type for Python using __slots__ and read-only variables. Apart from the enum with default positional argument values, this one adds another enum type using keyword arguments.

Short Enum Recipe (Python)

2013-01-31T14:16:06-08:00

Python recipe 577021 by Stephen Chappell (enum, quick, short). Revision 9.

If you want a small code snippet for enumerations in Python and the following code is sufficient for your needs, please go ahead and use it! Running the code is as simple as this: STATE = enum('GET_QUIZ, GET_VERSE, TEACH')

This recipe was edited and adapted after the author was inspired by seeing other, better enum recipes lying around.

Yet another enum for Python (Python)

2009-04-03T12:02:33-07:00

Python recipe 576711 by Antonio Cuni (enum).

There are plenty of ways to declare C-like enums in Python. This one tries to be minimalistic and with a nice syntax, (ab)using decorators.

The code is also available here: http://codespeak.net/svn/user/antocuni/hack/enum.py