3
我試圖學習描述符,並且被對象行爲困惑 - 在下面的兩個示例中,正如我理解的__init__
他們應該工作一樣。有人可能會否認我,或者指出一個解釋這一點的資源?使用__init__和設置類變量之間的區別
import math
class poweroftwo(object):
"""any time this is set with an int, turns it's value to a tuple of the int
and the int^2"""
def __init__(self, value=None, name="var"):
self.val = (value, math.pow(value, 2))
self.name = name
def __set__(self, obj, val):
print "SET"
self.val = (val, math.pow(val, 2))
def __get__(self, obj, objecttype):
print "GET"
return self.val
class powoftwotest(object):
def __init__(self, value):
self.x = poweroftwo(value)
class powoftwotest_two(object):
x = poweroftwo(10)
>>> a = powoftwotest_two()
>>> b = powoftwotest(10)
>>> a.x == b.x
>>> GET
>>> False #Why not true? shouldn't both a.x and b.x be instances of poweroftwo with the same values?
您可能希望在輸出中包含類型(a.x)和類型(b.x)。 – 2009-06-19 17:05:57