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...
else:delself When you see self in an Object's method it is just a reference to the object itself, del sel will just delete the local reference. If you really want to destroy an object you must destroy it with del on every reference. Python will forget about your object if no living ...
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...
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)...
stu5) # implementing the operator del Geek.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 error print('Fifth = ',names.stu5) 输出...
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 = ',...
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If you need to delete an item from an existing list, then you can use the del statement along with the indexing operator. The general syntax is:Python del a_list[index] This statement will remove the item that lives at the position defined by index in a_list. Here’s an example so...
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. ...