[問題] 使用dict["setattr"]取代現有的類別函數

看板Python作者rexrainbow ( hua)時間13年前 (2010/12/08 17:48)推噓2(2推 0噓 6→)

留言8則, 2人參與討論串1/1

操作物件內的__dict__字典相當於操作物件內的屬性存取. 雖然仍有些不同. obj.__dict__[name] = value # obj.name = value 然而以 obj.__dict__["__setattr__"] = new_fn 來取代現有的 __setattr__ 時遇到一個問題(使用python2.6): class aKlass: var = 0 def a_fn(self): print "aKlass.a_fn" def __setattr__(self, name, value): print "aKlass.__setattr__",name,value def new_a_fn(self): print "new_a_fn" def new_setattr_fn(self,name,value): print "new_setattr_fn",name,value aKlass內含兩個函數, a_fn, __setattr__. 另準備兩個對應的函數new_a_fn, new_setattr_fn 希望使用aKlass.__dict__[ ]的方式取代 -- aObj = aKlass() aObj.a_fn() aKlass.__dict__["a_fn"] = new_a_fn aObj.a_fn() aObj.var = 1 aKlass.__dict__["__setattr__"] = new_setattr_fn aObj.var = 1 執行結果: aKlass.a_fn new_a_fn aKlass.__setattr__ var 1 aKlass.__setattr__ var 1 aKlass.__dict__["a_fn"] = new_a_fn 的確用new_a_fn取代了原先的a_fn. 但似乎 aKlass.__dict__["__setattr__"] = new_setattr_fn 沒有達到預期的效果. 不知原因為何? (雖然使用 setattr(aKlass,"__setattr__",new_setattr_fn) 就可以取代原函數了.) -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 211.20.60.207

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