Does Python's enum class use partial string matching?

Question

I have an enum class representing time periods, but i'd like the have two different names for the same mapping

class TimePeriod(enum.IntEnum):
    DAILY = 1
    MONTH = 2
    MONTHLY = 2

However, when I access MONTH or MONTHLY I get the MONTH type as shown below:

TimePeriod.MONTH
returns: <TimePeriod.MONTH: 2>

TimePeriod.MONTHLY
returns: <TimePeriod.MONTH: 2>

Is Python's enum code using partial matching for the enumeration? This happens when I reverse the order of MONTH and MONTHLY in the class definition as well.

Answer 1

Enums are unique -- not by name, but by value. When a name for a value appears more than once, the name first seen is considered the canonical name for that value, and all other names for that same value are aliases.

From the docs:

Having two enum members with the same name is invalid:

>>>
>>> class Shape(Enum):
...     SQUARE = 2
...     SQUARE = 3
...
Traceback (most recent call last):
...
TypeError: Attempted to reuse key: 'SQUARE'
However, two enum members are allowed to have the same value.
Given two members A and B with the same value (and A defined
first), B is an alias to A. By-value lookup of the value of A
and B will return A. By-name lookup of B will also return A:

>>>
>>> class Shape(Enum):
...     SQUARE = 2
...     DIAMOND = 1
...     CIRCLE = 3
...     ALIAS_FOR_SQUARE = 2
...
>>> Shape.SQUARE
<Shape.SQUARE: 2>
>>> Shape.ALIAS_FOR_SQUARE
<Shape.SQUARE: 2>
>>> Shape(2)
<Shape.SQUARE: 2>

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Disclosure: I am the author of the Python stdlib Enum, the enum34 backport, and the Advanced Enumeration (aenum) library.