Getting value of enum on string conversion

Question

I have the following enum defined:

from enum import Enum
class D(Enum):
    x = 1
    y = 2

print(D.x)

now the printed value is

D.x

instead, I wanted the enum’s value to be print

What can be done to achieve this functionality?

Asked By: Vaibhav Mishra

||

Source

Answer 1

You are printing the enum object. Use the .value attribute if you wanted just to print that:

print(D.x.value)

See the Programmatic access to enumeration members and their attributes section:

If you have an enum member and need its name or value:
>>>
>>> member = Color.red
>>> member.name
'red'
>>> member.value
1

You could add a __str__ method to your enum, if all you wanted was to provide a custom string representation:

class D(Enum):
    def __str__(self):
        return str(self.value)

    x = 1
    y = 2

Demo:

>>> from enum import Enum
>>> class D(Enum):
...     def __str__(self):
...         return str(self.value)
...     x = 1
...     y = 2
... 
>>> D.x
<D.x: 1>
>>> print(D.x)
1

Answered By: Martijn Pieters

Answer 2

I implemented access using the following

class D(Enum):
    x = 1
    y = 2

    def __str__(self):
        return '%s' % self.value

now I can just do

print(D.x) to get 1 as result.

You can also use self.name in case you wanted to print x instead of 1.

Answered By: Vaibhav Mishra

Answer 3

The most straightforward dunder method to use is _repr_ instead of _str_ since it will also allow you to print it in that way also in lists.

class D(Enum):
  x = 1
  y = 2

  def __repr__(self):
      return self.value

print([D.x,D.y])
>>> [1, 2]

Answered By: Tomás Gomez Pizarro

Answer 4

In case you want to compare your enum members to Int values, a better way to do it would be to extend IntEnum:

from enum import IntEnum


class D(IntEnum):
    x = 1
    y = 2


print(D.x)

In this way you can compare values of your enum against integers without explicitly calling .value:

>>> D.x == 1
True

For more information you can check this part of the Python docs: Enum comparisons

Answered By: Julian Espinel

Answer 5

If you are going to print value using f-string then you can inherit your enum from both Enum and str. This way you can have both value and name of the object. For instance:

from enum import Enum


class D(str, Enum):
    x = 1
    y = 2

print(D.x)
print(f"{D.x}")

Outputs:

D.x
1

Inheriting just from Enum will always give a full qualified name.

class D(Enum):
    x = 1
    y = 2

print(D.x)
print(f"{D.x}")

Output

D.x
D.x

This is opposite to if you not inherit from anything where you will get value instead of name:

class D:
    x = 1
    y = 2


print(D.x)
print(f"{D.x}")

Output

1
1

That is why inheriting from both str and Enum you are getting both full qualified name and the value.

Answered By: Vlad Bezden

Getting value of enum on string conversion

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