python 枚举的漂亮打印

Question

假设我有以下内容：

from enum import Enum

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

作为print(Color)的输出，我想看到：

The colors are:
- RED
- GREEN
- BLUE

我试过：

from enum import Enum

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

    @classmethod
    def __str__(self):
        res = "The colors are:\n"
        for g in set(map(lambda c: c.name, Color)):
            res += '- ' + g + '\n'
        return res

但它只适用于 print(Color(1))。使用 print(Color) 时如何让它工作？

Answer 1

要覆盖 class 的打印，您可以在 metaclass[=22 上定义 __str__ =]:

from enum import Enum, EnumMeta class MyEnumMeta(EnumMeta): def __str__(cls): lines = [f"The {cls.__name__.lower()}s are:"] for member in cls: lines.append(f"- {member.name}") return '\n'.join(lines) class Color(Enum, metaclass=MyEnumMeta): RED = 1 GREEN = 2 BLUE = 3

演示：

>>> Color <enum 'Color'> >>> print(Color) The colors are: - RED - GREEN - BLUE >>> Color.RED <Color.RED: 1> >>> print(Color.RED) Color.RED

class 名称被发现：

>>> class Animal(Enum, metaclass=MyEnumMeta): ... cat = 'meow' ... dog = 'woof' ... badger = 'grrr' ... >>> print(Animal) The animals are: - cat - dog - badger

python 枚举的漂亮打印

Nice print of python Enum

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