def main_cor():
  import random
  i = random.randrange(0,29)
  with open('roll_call.txt', encoding='utf-8') as file_obj:
      contents = file_obj.read()
      stuff = contents.split(' ')
      s = stuff[i]
      str = s.encode('gbk')
      print(str.decode('gbk'))

from tkinter import *

def function():
  root = Tk()
  root.title('Roll_call')
  root.geometry('240x240') 
  b1 = Button(root,text = '按钮',bd = 2 ,bg = "green",width = 10,command=main_cor)
  b1.pack()
function()