如何在python

Question

我还在学习python，而且我仍然很难处理对象，我试图编写一个程序来计算项目中一组活动的关键路径，我已经能够获得活动的关键路径，并且它们被存储为嵌套对象列表，每个对象都有不同的属性，如id，前驱和持续时间，问题我＆＃ 39;我要打印出正确的结果，我想打印出持续时间最长的路径和提供该值的路径本身

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()

我已经打印出总持续时间，在这种情况下为10，我注释掉的最后一行是我最后一次尝试比较object_lists中的对象id，这是基于他们的个人持续时间，即属性＆ ＃39; ID＆＃39;和＆＃39; dur＆＃39;每个对象，所以基本上我想得到像这样的输出

项目的关键路径是B ==＆gt; D，项目总持续时间为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()