old_contents: import numpy as np
  import matplotlib.pyplot as plt
  from scipy.spatial import Voronoi, voronoi_plot_2d
  
  import csv
  
  COUNT_LIMIT = None
  SAMPLE_LIMIT = 100
  
  Points = []
  with open('cell_info.csv', 'r', encoding='utf_8') as obj_file:
      csv_file = csv.reader(obj_file)
      for cnt, line in enumerate(csv_file):
          if COUNT_LIMIT and cnt >= COUNT_LIMIT:  # 只读取前 k 个点
              break
          Points.append([float(line[1]), float(line[2])])  # make up data points
  
  # 随机抽取 n 个点
  if SAMPLE_LIMIT:
      points = np.array([Points[i] for i in np.random.choice(len(Points), size = SAMPLE_LIMIT)])
  else:
      points = np.array(Points)
  
  # compute Voronoi tesselation
  vor = Voronoi(points)
  
  # plot
  voronoi_plot_2d(vor)
  
  # colorize
  for region in vor.regions:
      if not -1 in region:
          polygon = [vor.vertices[i] for i in region]
          plt.fill(*zip(*polygon))
  
  plt.show()
new_contents: import numpy as np
  import matplotlib
  import matplotlib.pyplot as plt
  from scipy.spatial import Voronoi, voronoi_plot_2d
  import pandas
  
  import os
  
  COUNT_LIMIT = None
  SAMPLE_LIMIT = 20
  
  cell_info = pandas.read_csv('cell_info.csv', header=None, dtype={0: str, 1: float, 2:float}, nrows=COUNT_LIMIT)
  cell_info.columns = ("name", "x", "y")
  
  # 随机抽取
  if SAMPLE_LIMIT:
      cells = np.array([(cell_info["x"][i], cell_info["y"][i]) for i in np.random.choice(len(cell_info), size = SAMPLE_LIMIT)])
  else:
      cells = np.array(cell_info["x", "y"])
  
  # compute Voronoi tesselation
  vor = Voronoi(cells)
  
  # plot
  fig = voronoi_plot_2d(vor)
  fig.canvas.set_window_title("基站服务范围示意图")
  title = fig.suptitle("cell_info")
  ax = fig.gca()
  ax.set_aspect(1.)
  
  # colorize
  for region in vor.regions:
      if -1 not in region:
          polygon = [vor.vertices[i] for i in region]
          _ = ax.fill(*zip(*polygon)) # plt.fill((x0, x1, x2, x3, ...), (y0, y1, y2, y3, ...), color=None)
  
  plt.show()
subject: use pandas to load data and modified plot format