How changes made on an object in a list affect all elements

Question

Here is my problem,

from Link import Link

def generateCompartibleLinks(linksList):
    count =0
    updatedList =[]
    for i,item in enumerate(linksList):
        link = linksList[i];
        for j,item in enumerate(linksList):
            if not linksList[i].sharesNode(linksList[j]):
                link.addCompartibleLink(linksList[j])
        updatedList.append(link)
        print len(updatedList[i].compartibleLinks)
    return updatedList

link1 = Link("a","b",5)
link2 =Link("b","c",1)
link3 = Link("d","b",3)
link4 =Link("d","c",2)

list1 = [link2,link1,link3,link4]

list1 = generateCompartibleLinks(list1)

for link in list1:
    print str(len(link.compartibleLinks))+" : "+link.getLinkInfo()

I expect each of the links (link1,link2,link3, link4) to have a different set of compartibleLinks but once a change is made on any element in the list it's reflected on each of them which is not what I want. Here is class Link.

class Link(object):
    sendNode =None
    rcvNode =None
    timesToSchedule =1
    isScheduled = False
    compartibleLinks = []
    def __init__(self,sendNode,rcvNode,timesToschedule):
        self.sendNode=sendNode
        self.rcvNode = rcvNode
        self.timesToSchedule =timesToschedule

    def reduceTimeToSchedule(self):
        self.timesToSchedule -=1
        if  self.timesToSchedule<=0:
             self.timesToSchedule=0

    def needsToschedule(self):
        if  self.timesToSchedule==0:
            return False
        else:
            return True
    def addCompartibleLink(self,link):
        self.compartibleLinks.append(link)
    def isCompartible(self,link):
        return any(l == link for l in self.compartibleLinks);
        #if the link is not found in the set.
        return False;
    def sharesNode(self,link):
        return (self.sendNode==link.sendNode or self.rcvNode==link.rcvNode or self.rcvNode==link.sendNode or self.sendNode==link.rcvNode)
    def getLinkInfo(self):
        return 'sender: '+ self.sendNode+" , rec:"+self.rcvNode

I have tried to look at various solutions that seem related to my problem but nothing really works for me.

That's because you have just the one list per class, shared among instances. See the duplicate. — Martijn Pieters, Sep 07 '17 at 21:36
Thank you! You have saved my day. had spent days messing up! — Robert Kasumba, Sep 07 '17 at 21:44

score -1 · Answer 1 · answered Sep 07 '17 at 21:45

-1

If I correctly understand what you're asking, then I suggest you use the built-in map function that is used to apply a given function to an iterable(i.e. your list). Of course you have to modify the generateCompatibleLinks function to accept a link and not a whole list.

answered Sep 07 '17 at 21:45

kingJulian

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Could I get an explanation as to why my answer was downvoted? Thank you in advance! – kingJulian Sep 07 '17 at 21:49
Thanks for your support. I was able to identify the problem. It was about intitializing the compartibleLinks list outside the constructor. I didn't down you :-). I appreciate your help. – Robert Kasumba Sep 07 '17 at 21:57

How changes made on an object in a list affect all elements

1 Answers1