Question

根据给定的输入，我有一个类，该类的功能为图形添加了一条边。例如：如果输入为add James Larry 1，则将在权重（亲密度级别）为James的{{1}}和Larry之间添加一条边。该图是集合的字典，因此，键是节点，值（集合）是边。

因此，此功能具有以下参数：源，目标和权重。该类如下所示：

我正在尝试实现以下代码：

class DiGraph(object):

     # Create an empty graph.
    def __init__(self):
        ## A dictionary that stores an entry of a node, as the key, and a set of outgoing edges 
        # (destination node, weight) from the node, as its value.
        self.graph = {}

        ## Total number of edges in the graph.
        self.__numEdges = 0

        ## The largest edge distance.
        # self.__infinity = sys.maxint
        self.__infinity = sys.maxsize

        ## Holds the path from a source node to a given node.
        self.__pathToNode = None

        ## Accumulated distance from source to a node.
        self.__dist = None

### (...)

   def addEdge(self, src, dst, c=1):
        if ( src == None or dst == None or c <= 0 or src == dst ):
            return False

       # the edge set of src
        eSet = self.graph.get(src)
        e = Edge(dst,c) # new edge
        if eSet == None: 
            # no edge starting at src, so create a new edge set
            eSet = set()
            self.__numEdges += 1
        else:
            ed = self.getEdge(src,dst)
            if ( ed != None ):
                ed.setCost(c)
                return True
            else:
                self.__numEdges += 1

        eSet.add(e) # a set does not have duplicates

        self.graph[src] = eSet
        if not self.hasVertex(dst):
            self.addVertex(dst)

        return True

文件的第一行是：import DiGraph #Create an empty graph def main(): aGraph = {} f = open("infile.txt") contents = f.read() lines = contents.splitlines() word = [] for line in lines: word.append(line.split()) for i in range(len(word)): if word[i][0] == 'add': aGraph = DiGraph.DiGraph.addEdge(word[i][1], word[i][2], int(word[i][3])) return aGraph grafo = main()

当我尝试运行此代码时，正在向我显示此错误：

回溯（最近通话最近一次）：


文件
中的文件“ C：/.../ SocialGraph.py”，第24行

grafo = main（）


文件“ C：/.../ SocialGraph.py”在主行中的第20行


aGraph = DiGraph.DiGraph.addEdge（word [i] [1]，word [i] [2]，int（word [i] [3]））


addEdge中的文件“ C：... \ DiGraph.py”，第156行


eSet = self.graph.get（src）



AttributeError：'str'对象没有属性'graph'

该如何解决？

Answer 1

DiGraph.DiGraph.addEdge(word[i][1],

您将此称为静态方法。 'word [i] [1]'变成'self'。

Answer 2

您将addEdge实现为实例方法，因此必须创建一个实例才能使用它。像这样：

# create DiGraph instance
diGraph = DiGraph.DiGraph()

for i in range(len(word)):
        if word[i][0] == 'add':
            aGraph = diGraph.addEdge(word[i][1], word[i][2], int(word[i][3]))

'str'对象没有属性/调用字典时出错

2 个答案: