如何在python中打印具有最高总和的嵌套对象列表

Question

I'm still learning python and i'm still having a tough time working with objects, i'm trying to write a program that calculates the critical path of a set of activities in a project, I've been able to get the critical path of the activities and they're stored as a list of nested objects with each object having it's different properties like id, predecessor and duration, the problem i'm having is to print out the result properly, i want to print out the path that has the longest duration and the path itself that gives that value

class criticalPath:

    def __init__(self):
        '''
        Initialize all the variables we're going to use to calculate the critical path
        '''
        self.id = None
        self.pred = tuple()
        self.dur = None
        self.est = None
        self.lst = None
        #list to store all the objects
        self.all_objects = list()

    def set_properties(self, name, predecessor, duration):
        self.id = name
        self.pred = tuple(predecessor)
        self.dur = duration


def main():
    #starting_nodes = list()
    object_list = list()

    A = criticalPath()
    A.set_properties('A', '0', 3)

    B = criticalPath()
    B.set_properties('B', '0', 6)

    C = criticalPath()
    C.set_properties('C', 'A', 1)

    D = criticalPath()
    D.set_properties('D', 'B', 4)



    tmp_list = list()
    tmp_list.append(A)
    tmp_list.append(C)
    object_list.append(tmp_list)

    tmp_list = list()
    tmp_list.append(B)
    tmp_list.append(D)
    object_list.append(tmp_list)


    print('The total duration of the project is {}'.format(max([sum([node.dur for node in object]) for object in object_list])))
    #print(max(object_list.id, key=sum(object_list.dur)))


if __name__ == '__main__': main()

I've been able to print out the total duration which in this case is 10, the last line i commented out is my last attempt at comparing the objects id in object_lists based on their individual duration which is the property 'id' and 'dur' of each object, so basically i want to get an output like this

The critical path of the project is B==>D and the total duration of the project is 10

Answer 1

class criticalPath:

    def __init__(self):
        '''
        Initialize all the variables we're going to use to calculate the critical path
        '''
        self.id = None
        self.pred = tuple()
        self.dur = None
        self.est = None
        self.lst = None
        #list to store all the objects
        self.all_objects = list()

    def set_properties(self, name, predecessor, duration):
        self.id = name
        self.pred = tuple(predecessor)
        self.dur = duration


def main():
    #starting_nodes = list()
    object_list = list()

    A = criticalPath()
    A.set_properties('A', '0', 3)

    B = criticalPath()
    B.set_properties('B', '0', 6)

    C = criticalPath()
    C.set_properties('C', 'A', 1)

    D = criticalPath()
    D.set_properties('D', 'B', 4)

    tmp_list = list()
    tmp_list.append(A)
    tmp_list.append(C)
    object_list.append(tmp_list)

    tmp_list = list()
    tmp_list.append(B)
    tmp_list.append(D)
    object_list.append(tmp_list)

    print(object_list)

    print('The total duration of the project is {}'.format(max([sum([node.dur for node in object]) for object in object_list])))
    print([path.id for path in max(object_list, key=lambda ls: sum(obj.dur for obj in ls))])


if __name__ == '__main__': main()