Question

我有一个坐标为100点的文本文件，属于一些抛物线。每个点由具有以下结构的行描述：X_coordinate，Y_coordinate，ID，next_ID，tag。

ID是行号，next_ID是沿某个抛物线所考虑的点之后的点的ID。通常，next_ID != ID + 1。我希望我的脚本能够给出某个抛物线的所有点tag;你有什么建议怎么做吗？

输入文件看起来像

23.009   784.343  1  22 
472.844  387.843  2  0
32.899   209.027  3  23
345.283  294.034  4  24
[...]
48.939   778.283  22 35

我想要做的是添加一个标记列，以便

23.009   784.343  1  22  1 
472.844  387.843  2  0   0
32.899   209.027  3  23  2
345.283  294.034  4  24  3
[...]
48.939   778.283  22 35  1

下面你可以找到我提出的代码。如果可能的话，我想使用更加pythonic的解决方案; - ）

for i in range(0, Number_of_lines_in_txt):
    if next_ID[i] != 0:  # I check that the considered point has a following one along
                         # The considered parabola
        if tag[i] == 0:  # If the point is already tagged, we skip it
            tag = tag + 1
            tag[i] = tag
            #  Now we do the same for next_ID: we check if it has a following point, 
            #  We check if it has a tag.
            if next_ID[next_ID[i]] != 0: 
                if tag[next_ID[i]] == 0:
                    tag[next_ID[i]] == tag
                        #  Third iteration
                        if next_ID[next_ID[next_ID[i]]] != 0
                        [...]

Answer 1

所以看起来你想要做的是创建一个Point类，然后创建一个Point对象列表，并带有一些默认标记。最后，您需要在列表上执行深度优先搜索以创建标记。然后，您希望将Point写回文件，最好是为每个__repr__编写Point函数。

类似（未经测试，在答案框中写到）

class Point():
   tag = 0
   def __init__(self, xCoord, yCoord, id, nextID):
      self.xCoord = xCoord
      self.yCoord = yCoord
      self.id     = id
      self.nextID = nextID
  def __repr__(self):
     return "%f %f %d %d %d" % (xCoord, yCoord, id, nextID, tag)

"""do some file I/O, call readlines() to fill a list named lines"""

pointDictionary = {}

for line in lines:
   col = line.split()
   point = Point(float(col[0]), float(col[1]), int(col[2]), int(col[3]))
   pointDictionary[point] = False #unvisited for our DFS

#DFS
def DFS(nextPoint, pointDict, tag): #DFS from this point, setting all to same tag
   if pointDict[nextPoint] == True:
      return

   pointDict[nextPoint] = True
   nextPoint.tag = tag
   DFS(pointDict[nextPoint.nextID-1], pointDict, tag) #assuming IDs are from 1...n

tag = -1
for point in pointDictionary:
   if pointDictionary[point] == False:
      tag += 1
      DFS(point, pointDictionary, tag)


"""Now some I/O to simply write contents of
   pointDictionary (keys only) to an output file"""

编辑：我仍然不完全理解您分配标签的逻辑。我将遍历通过nextID s连接的所有点，并从0开始为它们分配标签。我假设这些点是有序的，这样可以通过遍历nextID s <到达抛物线中的所有点/ p>

订购连续点

1 个答案: