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我使用的是從列表中繼承的數據結構類:在Python中重寫'布爾'操作符?
class CItem(list) :
pass
oItem = CItem()
oItem.m_something = 10
oItem += [ 1, 2, 3 ]
一切都是完美的,但如果我用我的我的類的對象內部的「如果」,蟒蛇評估爲FALSE如果基礎列表中沒有元素。因爲我的課不只是名單,我真的希望它評估假,只有當它是無,和評價,否則真:
a = None
if a :
print "this is not called, as expected"
a = CItem()
if a :
print "and this is not called too, since CItem is empty list. How to fix it?"
+1因爲你似乎發現自己另一個美妙的Python寶石:) – 2009-08-14 21:35:28