json格式

0 字符串要""包裹
1 单个对象要在{} 中
2 多个对象要在[ {1}, {2}, {3}, {4}] 中

    def toJson(self):
        """
        将图保存为json格式
        :return:
        """
        
        id = " \"id\" : " + "\"" + self.id + "\""
        loc = "\"loc\" : " + "\"" + self.long + "_" + self.lat + "\""
        adjacent = "\"adjacent\" : ["
        for v, v_weight in self.adjacent.items():
            adjacent += "{ " + "\"adj_id\" : " + "\"" + str(v.id) + "\"" + "," \
                        + "\"loc\" : " + "\"" + v.long + "_" + v.lat + "\"" + "," \
                        + "\"weight\" : " + str(v_weight) + "} ,"
        adjacent = adjacent.rstrip(",") + ' ]'

        return "{" + id + ", " + loc + ", " + adjacent + " }"