How to Implement an 'enum' in Python

In Python, you can implement an enum using the Enum class from the enum module. Here’s an example:

from enum import Enum

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

Alternatively, you can use namedtuple from the collections module to define your custom data type as well. Here’s an example to create an enumeration of programming languages:

from collections import namedtuple

Language = namedtuple('Language', 'name version')

PYTHON = Language('Python', '3.9')
JAVASCRIPT = Language('JavaScript', 'ES6')
JAVA = Language('Java', '11')

You can then access the enumeration values like this:

# access an enum value by name
color = Color.RED

# iterate over all enum values
for color in Color:
    print(color)

That’s how you can create and use enumerations in Python.

To create an enumeration in NumPy

To create an enumeration in NumPy, you can use the IntEnum class from the enum module along with a NumPy array to define the enumeration values. Here’s an example:

from enum import IntEnum
import numpy as np

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

# create an array of the enumeration values
color_array = np.array([Color.RED, Color.BLUE, Color.GREEN])

# access an enumeration value by index
print(color_array[0])    # output: Color.RED

You can also use the EnumArray class from the numpy.lib.enum module to create an array of enumeration values. Here’s an example:

from numpy.lib.enum import EnumArray
import numpy as np

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

# create an array of the enumeration values
color_array = EnumArray(['RED', 'GREEN', 'BLUE'], Color)

# access an enumeration value by index
print(color_array[0])    # output: Color.RED

Both of these methods allow you to work with enumerations in NumPy arrays.