Python枚举对比技巧与应用

from enum import Enum
<p>class Color(Enum):
RED = 1
GREEN = 2
BLUE = 3</p><p>print(Color.RED == Color.RED)      # True
print(Color.RED == Color.GREEN)    # False
print(Color.RED is Color.RED)      # True（同一对象）</p>

class Status(Enum):
    ACTIVE = 1
<p>print(Color.RED == Status.ACTIVE)  # False</p>

from enum import IntEnum
<p>class Priority(IntEnum):
LOW = 1
MEDIUM = 2
HIGH = 3</p><p>print(Priority.LOW < Priority.HIGH)   # True
print(Priority.MEDIUM == 2)         # True
print(Priority.HIGH > 2)            # True</p>

# 推荐方式：显式取值比较
if some_priority.value >= 2:
    print("Medium or higher")
<h1>而不是依赖隐式比较</h1>

class State(Enum):
    STOPPED = 1
    RUNNING = 2
    PAUSED = 3
<pre class="brush:python;toolbar:false;">def comes_before(self, other):
    order = [State.STOPPED, State.RUNNING, State.PAUSED]
    return order.index(self) < order.index(other)

print(State.RUNNING.comes_before(State.PAUSED)) # True