del x并不会立刻调用x.__del__(). 每当遇到del x, Python 会将x的引用数减1, 当x的引用数减到0时就会调用x.__del__(). 在第二个例子中,y.__del__()之所以未被调用, 是因为前一条语句 (>>> y) 对同一对象创建了另一个引用, 从而防止在执行del y后对象的引用数变为0. 调用globals导致引用...
del operator O(n) iteration O(n) contains(in) O(n) get slice[x:y] O(k) del slice O(n) set slice O(n+k) reverse O(n) concatenate O(k) sort O(nlogn) multiply O(nk) O括号里面的值越大代表效率越低 由此可见,如果算法中采用 pop( index) 的做法去删除数据,其实空间复杂度已经是 ...
obj not in seq 判断 obj 元素是否不包含在 seq 中 成员关系操作符 (in, not in) 成员关系操作符用于判断一个元素是否属于一个序列。比如对字符串类型来说,就是判断一个字符是否属于这个字符串,对和元组类型来说,就代表了一个对象是否属于该对象序列。in/not in 操作符的返回值一般来讲就是 True/False,满...
insert(i,item) O(n) del operator O(n) iteration O(n) contains(in) O(n) get slice[x:y] O(k) del slice O(n) set slice O(n+k) reverse O(n) concatenate O(k) sort O(nlogn) multiply O(nk) O括号里面的值越大代表效率越低 由此可见,如果算法中采用 pop( index) 的做法去删除数据...
1 Python: Understanding object __del__ method 2 Why doesn't __del__ work properly 3 Does python always call __del__ synchronously? 2 Behavior of del operator in Python 37 What does "del" do exactly? 1 Why doesn't del do the same thing? 19 Is __del__ really a destructor?
Python中有另一个运算符与 delattr() 方法执行类似的工作。它是del运算符。让我们看看它是如何工作的。 Python3 # Python code to illustrate del()classGeek:stu1="Henry"stu2="Zack"stu3="Stephen"stu4="Amy"stu5="Shawn"names=Geek()print('Students before del--')print('First = ',names.stu1)...
print('Fifth = ',names.stu5)# implementing the operatordelGeek.stu5 print('After deleting fifth student--') print('First = ',names.stu1) print('Second = ',names.stu2) print('Third = ',names.stu3) print('Fourth = ',names.stu4)# this statement raises an errorprint('Fifth = ',...
File "python", line 19, in <module> AttributeError: 'Coordinate' object has no attribute 'z' Here, attributezis removed from theCoordinateclass usingdelattr(Coordinate, 'z'). Example 2: Deleting Attribute Using del Operator You can also delete attribute of an object usingdeloperator. ...
Cambia i valori del dizionario in Python decomprimendo il dizionario usando l’operatore *In questo metodo, possiamo modificare i valori del dizionario decomprimendo il dizionario utilizzando l’operatore * e quindi aggiungendo una o più coppie chiave-valore di cui vogliamo modificare il dizi...
In that sense, it's roughly equivalent to several python features that are used to access built-in functionality at a lower level than you normally have available, such as __import__ instead of import and operator.add instead of + Share Improve this answer Follow answered Jul 13, 2009 at...