Recipe for Python Enum class that builds on the "FOO = 1" pattern by adding a printable name.
In other words, an Enum instance is a named integer.
Python, 38 lines
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Copy to clipboard1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 | """Enumeration class representing a named integer."""
class Enum(int):
"""Enumeration value is a named integer."""
#pylint: disable=R0904
def __new__(cls, rank, name):
obj = int.__new__(cls, rank)
obj.name = name
return obj
def __repr__(self):
return 'Enum(' + repr(int(self)) + ', ' + repr(self.name) + ')'
@staticmethod
def lookup(enumvals):
"""Lookup from int/string to Enum instance for provided values"""
result = {int(v): v for v in enumvals}
result.update({v.name: v for v in enumvals})
return result
def test():
"""Tests of the Enum class"""
# pylint: disable=C0103
WEAK = Enum(1, 'WEAK')
MODERATE = Enum(2, 'MODERATE')
STRONG = Enum(3, 'STRONG')
assert repr(STRONG) == "Enum(3, 'STRONG')"
assert WEAK < MODERATE < STRONG
assert MODERATE > WEAK
assert WEAK.name == 'WEAK'
assert WEAK == 1
assert WEAK < 3
if __name__ == '__main__':
test()
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Useful if all you want from your Enum values is to have them come with a readable name, whether for display or debugging purposes.
Features:
- Enum is just an int, with a name attached.
- Explicit declaration just like stdlib (logging.DEBUG, re.MULTILINE)
Tags: enum
