python - 在 python 中返回了错误的列表

Question

def mainCall(nodeGroup):

    maxScore = -9999999
    maxPart = []
    tempPartition = []
    tempScore = 0.0

    for j in range(2, 1+nodes/2):

        nodeGroup = chooseInitPartition(j, nodeGroup)
        tempScore, tempPartition = runKL(edgeList, nodeGroup, rounds)
        print 'temp score', tempScore
        print 'temp part', tempPartition, "\n"
        if(maxScore < tempScore):
            maxScore = tempScore
            maxPart = tempPartition
            print "max score", maxScore
            print "maxpart", maxPart, "\n"

     print 'before ret max part', maxPart
     return maxScore, maxPart

finalScore, finalPartition = mainCall(nodeGroup)

上面的代码有问题。在 for 循环结束之前一切似乎都很好，但在那之后不是在 print 'before ret max part' 行打印 maxPart 值，它打印 tempPartition 的最后一个值(两者都代表一个数字列表)。 打印语句确认每次都不满足 if 条件，尤其是循环中的最后几次运行。所以我看不到 tempPartition 的值是如何传输到 maxPart 的。请在这件事上给予我帮助。这让我发疯。我确定我错过了一些简单的东西。谢谢!

编辑:

为 runKL 添加代码

def runKL(edgeList, nodeGroup, rounds):

    nodeSwap = [0]*nodes
    maxLogLScore = 0.0
    edgeListLen = len(edgeList)

    networkPartitionStore = []
    logLScores = []

    #Reset count
    count = 0

    #Start main loop
    for i in range(rounds):
        #mark all vertices as unswapped
        for j in range(len(nodeSwap)):
            nodeSwap[j] = 0


        while(count < 100):
            #Choose one edge uniformly randomly
            randNum = random.uniform(0,1)
            edge = edgeList[int(math.floor(edgeListLen*randNum))]
            node1 = int(edge[0]) - 1
            node2 = int(edge[1]) - 1

            if((nodeGroup[node1] == nodeGroup[node2]) or (nodeSwap[node1] == 1) or (nodeSwap[node2] == 1)):
                count += 1
                continue
            else:
                #swap groups among nodes
                temp = nodeGroup[node1]
                nodeGroup[node1] = nodeGroup[node2]
                nodeGroup[node2] = temp

                #mark vertices as swapped
                nodeSwap[node1] = 1
                nodeSwap[node2] = 1

                #calculate likelihood
                logLScore = logLikelihood(edgeList, nodeGroup)
                logLScores.append(logLScore)

                #store network
                networkPartitionStore.append(nodeGroup)

                #reset count value
                count = 0

        #end while loop

        #Choose the index of the maximum likelihood score
        maxLogLScore = max(logLScores)
        index = logLScores.index(maxLogLScore)
        #print 'max score', modularityScores[index]

        #Choose the corresponding network partition i.e. the way the groups have been assigned to the nodes
        nodeGroup = networkPartitionStore[index]

        #Reset partition storage list and modularity scores
        networkPartitionStore = []
        logLScores = []

        #Store initial network partition structure and modularity score. 
        networkPartitionStore.append(nodeGroup)
        logLScores.append(maxLogLScore)

    return maxLogLScore, nodeGroup

Answer 1

当你说

maxPart = tempPartition

您不是在创建 tempPartition 的副本，而是让 maxPart 也指向 tempPartition 指向的同一个列表。要真正制作副本，您可以使用这样的切片符号

maxPart[:] = tempPartition

或

maxPart = tempPartition[:]

maxPart[:] = tempPartition 和 maxPart = tempPartition[:] 的区别在于前者改变了 maxPart 并复制了所有从 tempPartition 到 maxPart 的值，后者创建一个新列表，其中包含 tempPartition 中所有数据的副本，并使 maxPart 指向新创建的列表。