Priya R
Updated date May 23, 2023
In this blog, we will explore several methods for converting an integer to an enumeration in Python, including using the Enum class, dictionary mappings, and class methods. It provides example code and explanations for each method and concludes by highlighting the benefits of using enumerations to write more maintainable and less error-prone code.

## Introduction:

In Python, an enumeration is a set of named integer constants. Enumerations are useful for creating more descriptive and self-documenting code, as well as for avoiding hardcoding magic numbers into your code. Sometimes, you may have an integer value that corresponds to a particular enumeration value, and you may need to convert that integer into an enumeration. In this blog post, we will explore several methods for converting an integer to an enumeration in Python.

## Method 1: Using the Enum Class

The most straightforward method for converting an integer to an enumeration in Python is to use the Enum class. First, define an enumeration using the Enum class and assign integer values to each of the enumeration members. Then, use the Enum class's `call()` method to convert the integer value to the corresponding enumeration member.

Here's an example:

``````from enum import Enum

class Color(Enum):
RED = 1
GREEN = 2
BLUE = 3

color_int = 2
color_enum = Color(color_int)

print(color_enum)
``````

### Output:

``````Color.GREEN
``````

Explanation: In this example, we define an enumeration called "Color" that has three members: RED, GREEN, and BLUE. We assign the integer value 1 to RED, 2 to GREEN, and 3 to BLUE. Then, we define an integer variable called "color_int" and assign it the value 2. To convert this integer value to the corresponding enumeration member, we pass it as an argument to the `Color()` constructor, which is a shorthand for calling the Enum class's `call()` method. The result is an instance of the Color enumeration that corresponds to the value 2, which in this case is Color.GREEN.

## Method 2: Using a Dictionary Mapping

Another method for converting an integer to an enumeration in Python is to use a dictionary mapping. First, define a dictionary that maps integer values to the corresponding enumeration members. Then, use the dictionary to look up the enumeration member corresponding to the integer value.

Here's an example:

``````from enum import Enum

class Color(Enum):
RED = 1
GREEN = 2
BLUE = 3

color_int = 2
color_dict = {1: Color.RED, 2: Color.GREEN, 3: Color.BLUE}
color_enum = color_dict[color_int]

print(color_enum)
``````

### Output:

``````Color.GREEN
``````

In this example, we define an enumeration called "Color" that has three members: RED, GREEN, and BLUE. We assign the integer value 1 to RED, 2 to GREEN, and 3 to BLUE. Then, we define an integer variable called "color_int" and assign it the value 2. To convert this integer value to the corresponding enumeration member, we define a dictionary called "color_dict" that maps integer values to the corresponding enumeration members. We then look up the enumeration member corresponding to the integer value 2 using the dictionary and assign it to the variable "color_enum". The result is an instance of the Color enumeration that corresponds to the value 2, which in this case is Color.GREEN.

## Method 3: Using a Class Method

Another method for converting an integer to an enumeration in Python is to define a class method that takes an integer argument and returns the corresponding enumeration member. This method can be defined on the enumeration class itself or on a separate utility class.

Here's an example:

``````from enum import Enum

class Color(Enum):
RED = 1
GREEN = 2
BLUE = 3

@classmethod
def from_int(cls, color_int):
for color in cls:
if color.value == color_int:
return color
raise ValueError(f"No matching color for integer value {color_int}")

color_enum = Color.from_int(3)

print(color_enum)
``````

### Output:

``````Color.BLUE
``````

In this example, we define the same enumeration called "Color" with three members and integer values assigned to each. However, instead of using a dictionary mapping or the call() method, we define a class method called "from_int" that takes an integer argument called "color_int". This method works by iterating over all the enumeration members using the cls iterator and comparing the value of each member to the integer argument. When it finds a match, it returns the corresponding enumeration member. If no match is found, it raises a `ValueError` with a helpful error message. To convert the integer value 3 to the corresponding enumeration member, we call the "from_int" method on the Color enumeration class and pass 3 as an argument. The result is an instance of the Color enumeration that corresponds to the value 3, which in this case is Color.BLUE.

Overall, the class method approach provides a more flexible and dynamic way of converting integers to enumerations compared to the dictionary mapping approach, as it allows for more complex logic to be implemented in the method if needed.

## Conclusion:

In this blog post, we have explored several methods for converting an integer to an enumeration in Python. The first method involved using the Enum class and the __call__() method. The second method involved using dictionary mapping. The third method involved defining a class method that takes an integer argument and returns the corresponding enumeration member.