How to convert int to Enum in python?

Question

Using the new Enum feature (via backport enum34) with python 2.7.6.

Given the following definition, how can I convert an int to the corresponding Enum value?

from enum import Enum

class Fruit(Enum):
    Apple = 4
    Orange = 5
    Pear = 6

I know I can hand craft a series of if-statements to do the conversion but is there an easy pythonic way to convert? Basically, I'd like a function ConvertIntToFruit(int) that returns an enum value.

My use case is I have a csv file of records where I'm reading each record into an object. One of the file fields is an integer field that represents an enumeration. As I'm populating the object I'd like to convert that integer field from the file into the corresponding Enum value in the object.

Answer 1

You 'call' the Enum class:

Fruit(5)

to turn 5 into Fruit.Orange:

>>> from enum import Enum
>>> class Fruit(Enum):
...     Apple = 4
...     Orange = 5
...     Pear = 6
... 
>>> Fruit(5)
<Fruit.Orange: 5>

From the Programmatic access to enumeration members and their attributes section of the documentation:

Sometimes it’s useful to access members in enumerations programmatically (i.e. situations where Color.red won’t do because the exact color is not known at program-writing time). Enum allows such access:

>>> Color(1)
<Color.red: 1>
>>> Color(3)
<Color.blue: 3>

In a related note: to map a string value containing the name of an enum member, use subscription:

>>> s = 'Apple'
>>> Fruit[s]
<Fruit.Apple: 4>