从csv数据集创建python中的邻接矩阵

1 回答

• 4

  这是一个解决方案 . 它不直接为您提供所请求的邻接矩阵，而是为您提供自己创建它所需的内容 .

  #assume you stored every line of your input as a tuples (eventid, mnbr).
  observations = [(20, 1), (26, 1), (12, 2), (14, 2), (15,3 ), (14, 3), (10, 3)]
  
  #then creates an event link dictionary. i.e something that link every event to all its mnbrs
  eventLinks = {}
  
  for (eventid, mnbr) in observations :
      #If this event have never been encoutered then create a new entry in links
      if not eventid in eventLinks.keys():
          eventLinks[eventid] = []
  
      eventLinks[eventid].append(mnbr)
  
  #collect the mnbrs
  mnbrs = set([mnbr for (eventid, mnbr) in observations])
  
  #create a member link dictionary. This one link a mnbr to other mnbr linked to it.
  mnbrLinks = { mnbr : set() for mnbr in mnbrs }
  
  for mnbrList in eventLinks.values() :
      #add for each mnbr all the mnbr implied in the same event.
      for mnbr in mnbrList:
          mnbrLinks[mnbr] = mnbrLinks[mnbr].union(set(mnbrList))
  
  print(mnbrLinks)
  

  执行此代码会产生以下结果：

  {1: {1}, 2: {2, 3}, 3: {2, 3}}
  

  这是一个字典，其中每个 mnbr 都有一组相关的邻接 mnbrs . 这实际上是一个邻接列表，它是一个压缩的邻接矩阵 . 您可以使用字典键和值作为行和列索引来扩展它并构建您请求的矩阵 .

  希望它有所帮助 . 亚瑟 .

  编辑：我提供了一种使用邻接列表的方法，让您实现自己的邻接矩阵构建 . 但是，如果数据稀疏，您应该考虑真正使用此数据结构 . 见http://en.wikipedia.org/wiki/Adjacency_list

  编辑2：添加代码以将adjacencyList转换为一个小的智能adjacencyMatrix

  adjacencyList = {1: {1}, 2: {2, 3}, 3: {2, 3}}
  
  class AdjacencyMatrix():
  
      def __init__(self, adjacencyList, label = ""):
          """ 
          Instanciation method of the class.
          Create an adjacency matrix from an adjacencyList.
          It is supposed that graph vertices are labeled with numbers from 1 to n.
          """
  
          self.matrix = []
          self.label = label
  
          #create an empty matrix
          for i in range(len(adjacencyList.keys())):
              self.matrix.append( [0]*(len(adjacencyList.keys())) )
  
          for key in adjacencyList.keys():
              for value in adjacencyList[key]:
                  self[key-1][value-1] = 1
  
      def __str__(self):
          # return self.__repr__() is another possibility that just print the list of list
          # see python doc about difference between __str__ and __repr__
  
          #label first line
          string = self.label + "\t"
          for i in range(len(self.matrix)):
              string += str(i+1) + "\t"
          string += "\n"
  
          #for each matrix line :
          for row in range(len(self.matrix)):
              string += str(row+1) + "\t"
              for column in range(len(self.matrix)):
                  string += str(self[row][column]) + "\t"
              string += "\n"
  
  
          return string
  
      def __repr__(self):
          return str(self.matrix)
  
      def __getitem__(self, index):
          """ Allow to access matrix element using matrix[index][index] syntax """
          return self.matrix.__getitem__(index)
  
      def __setitem__(self, index, item):
          """ Allow to set matrix element using matrix[index][index] = value syntax """
          return self.matrix.__setitem__(index, item)
  
      def areAdjacent(self, i, j):
          return self[i-1][j-1] == 1
  
  m = AdjacencyMatrix(adjacencyList, label="mbr")
  print(m)
  print("m.areAdjacent(1,2) :",m.areAdjacent(1,2))
  print("m.areAdjacent(2,3) :",m.areAdjacent(2,3))
  

  此代码提供以下结果：

  mbr 1   2   3   
  1   1   0   0   
  2   0   1   1   
  3   0   1   1   
  
  m.areAdjacent(1,2) : False
  m.areAdjacent(2,3) : True
  

  回复于 2024-05-02T08:58:26+08:00