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Python有序链表与引用正确名称的混淆_Python_Python 3.x_Linked List - Fatal编程技术网

Python有序链表与引用正确名称的混淆

Python有序链表与引用正确名称的混淆,python,python-3.x,linked-list,Python,Python 3.x,Linked List,我在看这个链表,它是一个有序链表。以下代码供参考: class Node: def __init__(self,initdata): self.data = initdata self.next = None def getData(self): return self.data def getNext(self): return self.next def setData(self,newda

我在看这个链表,它是一个有序链表。以下代码供参考:

class Node:
    def __init__(self,initdata):
        self.data = initdata
        self.next = None

    def getData(self):
        return self.data

    def getNext(self):
        return self.next

    def setData(self,newdata):
        self.data = newdata

    def setNext(self,newnext):
        self.next = newnext

class OrderedList:
    def __init__(self):
        self.head = None

    def add(self,item):
        current = self.head
        previous = None
        stop = False
        while current != None and not stop:
            if current.getData() > item:
                stop = True
            else:
                previous = current
                current = current.getNext()

        temp = Node(item)
        if previous == None:
            temp.setNext(self.head)
            self.head = temp
        else:
            temp.setNext(current)
            previous.setNext(temp)

    def isEmpty(self):
        return self.head == None

    def size(self):
        current = self.head
        count = 0
        while current != None:
            count = count + 1
            current = current.getNext()

        return count


mylist = OrderedList()
mylist.add(31)
mylist.add(77)
mylist.add(17)
mylist.add(93)
mylist.add(26)
mylist.add(54)

print(mylist.size())
如您所见,当调用mylist.size时,它将返回6的大小,因为添加了6项内容。但是在add方法中,特别是行:

if previous == None:
            temp.setNext(self.head)
            self.head = temp
如果我将self.head=temp更改为current=temp,它将返回0的大小。这意味着其余的数字没有被引用。但为什么会是这种情况,我想既然我们之前定义了current=self.head,那么将self.head=temp更改为current=temp会得到相同的结果

current = self.head
current = temp
上面的第一行将使current指向self.head所指的任何内容。 第二行使current表示温度,但它不使self.head表示温度

您可以将current视为对某个底层对象的引用,而self.head恰好也引用了该对象。将电流重新指定给温度不会改变self.head所指的内容

在使用Python时,这可能是一个常见的混淆,关于对象和名称的处理方式有很多信息。见例