python - 如何在调用函数后存储输出并在下次运行中使用它

Question

我在解释器中运行了以下代码并调用了 union 函数

quick_find(10).union(3,4)

输出:[0,1,2,4,4,5,6,7,8,9]

quick_find(10).union(0,4)

输出:[4,1,2,3,4,5,6,7,8,9]

当我第二次调用 union 函数时，输出列表应该是这样的
[4,1,2,4,4,5,6,7,8,9]。

但它却给了我 [4, 1, 2, 3, 4, 5, 6, 7, 8, 9] 作为输出。我怎样才能得到我想要的输出。请推荐

class quick_find:

    def __init__(self,n):
        self.id = [number for number in xrange(n)]


    def union(self,x,y):
        j = 0
        elements = self.id
        for i in elements:
            if i == elements[x]:
                elements[j] = elements[y]
            j = j+1

        self.id = elements
        return elements 

Answer 1

您实际上每次都在新实例上调用 union() 方法:

代码的改进版本:

class Quick_find:
    def __init__(self,n):
        self.id = range(n)    #just range() is enough

    def union(self,x,y):
        for i,elem in enumerate(self.id):    #use enumerate() for indexes
            if elem==x:
                self.id[i]=y

    def show(self):
        print self.id

q=Quick_find(10)       #create a instance
q.union(3,4)           #call union on that instance
q.union(0,4)           #call union on that instance
q.show()               

输出:

[4, 1, 2, 4, 4, 5, 6, 7, 8, 9]