Construct an Enum from a Dictionary in Python

Construct an Enum from a Dictionary in Python #

Use the functional API to construct an enum from a dictionary, e.g. Sizes = Enum('Sizes', my_dict). The first argument we pass to the Enum class is the name of the enumeration, and the second - the source of the enumeration member names and values.

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from enum import Enum

my_dict = {
    'SMALL': 1,
    'MEDIUM': 2,
    'LARGE': 3
}

Sizes = Enum('Sizes', my_dict)

print(Sizes)  # 👉️ <enum 'Sizes'>

print(Sizes.SMALL.name)  # 👉️ SMALL
print(Sizes.SMALL.value)  # 👉️ 1

We used the functional API for enum creation.

The second argument can be:

• a mapping (e.g. a dictionary)
• a sequence of tuples with 2 elements (key and value)
• whitespace-separated string of names
• a sequence of names

The Sizes enum we created using the functional API is equivalent to the following enum.

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from enum import Enum


class Sizes(Enum):
    SMALL = 1
    MEDIUM = 2
    LARGE = 3


print(Sizes.SMALL.name)  # 👉️ SMALL
print(Sizes.SMALL.value)  # 👉️ 1

If we pass a dictionary to the functional API, we assign the values of the dictionary as the values for the corresponding keys.

If we use a whitespace-separated string of names or a sequence of names, the enum values get auto-assigned increasing integers starting with 1.

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from enum import Enum


Sizes = Enum('Sizes', 'SMALL MEDIUM LARGE')

print(Sizes)  # 👉️ <enum 'Sizes'>

print(Sizes.SMALL.name)  # 👉️ SMALL
print(Sizes.SMALL.value)  # 👉️ 1

print(Sizes.MEDIUM.name)  # 👉️ MEDIUM
print(Sizes.MEDIUM.value)  # 👉️ 2

The code sample creates the same enum as in the previous examples.

You can optionally pass a start argument to the functional API if you need to specify a different starting value.

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from enum import Enum

Sizes = Enum('Sizes', 'SMALL MEDIUM LARGE', start=10)

print(Sizes)  # 👉️ <enum 'Sizes'>

print(Sizes.SMALL.name)  # 👉️ SMALL
print(Sizes.SMALL.value)  # 👉️ 10

print(Sizes.MEDIUM.name)  # 👉️ MEDIUM
print(Sizes.MEDIUM.value)  # 👉️ 11