如何在此 class 中獲得排序成員？

Question

我有以下 class：

class ExampleValue:
    NULL        = 'null'
    BOOLEAN     = 'true'
    INTEGER     = '4'
    FLOAT       = '?'
    DECIMAL     = '?'
    STRING      = '"HELLO"'
    BYTES       = 'b"xyz"'
    DATE        = 'DATE "2014-01-01"'
    TIME        = 'TIME "01:02:03"'
    DATETIME    = 'DATETIME "2014-01-01T01:02:03"'
    INTERVAL    = 'INTERVAL 4 HOUR'
    GEOGRAPHY   = 'POINT(1 1)'
    JSON        = 'JSON "[1,2,3]"'
    STRUCT      = '{"x": 2}'
    ARRAY       = '[1,2,3]'

我想從第一個迭代到最后一個。 有沒有辦法在保持訂購的同時做到這一點（或者我應該使用與 class 不同的“類型”？）。 我目前的做法是：

>>> for val in ExampleValue.__dict__: # or dir(ExampleValue)
...     if not val.startswith('_'):
...         print (val)
...
INTERVAL
STRING
DECIMAL
FLOAT
BYTES
DATETIME
STRUCT
JSON
BOOLEAN
TIME
DATE
INTEGER
ARRAY
NULL
GEOGRAPHY

Answer 1

您幾乎可以按原樣執行此操作，只需將enum class 子類化即可。 例如：

from enum import Enum

class ExampleValue(Enum):
    NULL        = 'null'
    BOOLEAN     = 'true'
    INTEGER     = '4'
    FLOAT       = '?'
    DECIMAL     = '?'
    STRING      = '"HELLO"'
    BYTES       = 'b"xyz"'
    DATE        = 'DATE "2014-01-01"'
    TIME        = 'TIME "01:02:03"'
    DATETIME    = 'DATETIME "2014-01-01T01:02:03"'
    INTERVAL    = 'INTERVAL 4 HOUR'
    GEOGRAPHY   = 'POINT(1 1)'
    JSON        = 'JSON "[1,2,3]"'
    STRUCT      = '{"x": 2}'
    ARRAY       = '[1,2,3]'

for val in ExampleValue:
    print (val.name, val.value)
NULL null
BOOLEAN true
INTEGER 4
FLOAT ?
STRING "HELLO"
BYTES b"xyz"
DATE DATE "2014-01-01"
TIME TIME "01:02:03"
DATETIME DATETIME "2014-01-01T01:02:03"
INTERVAL INTERVAL 4 HOUR
GEOGRAPHY POINT (1 1)
JSON JSON "[1,2,3]"
STRUCT {"x": 2}
ARRAY [1,2,3]

Answer 2

也許這可以幫助：

class Example(object):
    bool143 = True
    bool2 = True
    blah = False
    foo = True
    foobar2000 = False

example = Example()
members = [attr for attr in dir(example) if not callable(getattr(example, attr)) and not attr.startswith("__")]
print members