在python中订购枚举值

在python中订购枚举值

您的Enum在3个地方丢失了订单。首先，将类主体上的属性存储在字典中，然后将项目复制到另一个字典中。最后，您

values()

将返回第三个字典。字典不保存顺序，并且不可能在类主体中获得属性的顺序。

有了这个系统，最简单的就是拥有一个变量

__ordering__ = [ 'single', 'double' ]

并将

values()

返回值作为元组列表（如

dict.items()

）。

class Enummeta(type):    def __new__(typ, name, bases, attrs):        cls_attrs = {}        cls_choices = {}        for attr_name, value in attrs.items(): cls_attrs[attr_name] = attr_name.lower() if not attr_name.startswith("__"):     cls_choices[attr_name.lower()] = value        ordering = attrs.get('__ordering__')        if ordering == None: ordering = sorted(cls_choices.keys())        def choices(cls): return dict(cls_choices)        def values(cls, value=None): if value is None:     return [ (k, cls_choices[k] ) for k in ordering ] elif not isinstance(value, basestring):     return [ (k, cls_choices[k] ) for k in value ] else:     return unipre(cls_choices.get(value))        def keys(cls, nil=False): items = list(ordering) if nil:     items.append('') return items        def combined_length(cls): return len(",".join(cls.values().keys()))        def max_length(cls): return max(map(len, cls.values().keys()))        cls_attrs['choices'] = classmethod(choices)        cls_attrs['values'] = classmethod(values)        cls_attrs['keys'] = classmethod(keys)        cls_attrs['combined_length'] = classmethod(combined_length)        cls_attrs['max_length'] = classmethod(max_length)        return type(name, bases, cls_attrs)class SideHemType:    __ordering__ = ['double', 'single']    __metaclass__ = Enummeta    Single = "Single side hem for opaque fabrics"    Double = "Double side hem for transparent fabrics"print SideHemType.keys()print SideHemType.values()