Python偏函数应用举例-路灯指示牌

 1 #!/usr/bin/env python
 2 # _*_coding:utf-8_*_
 3 # 红绿灯练习：按照指示类型创建适当当景、背景色的路灯指示牌
 4 from functools import partial as pto
 5 from tkinter import Tk, Button,X
 6 from tkinter.messagebox import showinfo,showwarning,showerror
 7 WARN = 'warn'
 8 CRIT = 'crit'
 9 REGU = 'regu'
10 
11 SIGNS = {
12     'do not enter':CRIT,
13     'railroad crossing':WARN,
14     '55\nspeed limit':REGU,
15     'wrong way': CRIT,
16     'merging traffic': WARN,
17     'one way': REGU,
18 }
19 
20 critCB = lambda: showerror('Error','Error Button Pressed!')
21 warnCB = lambda: showwarning('Warning','Warning Button Pressed!')
22 infoCB = lambda: showinfo('Info','Info Button Pressed!')
23 
24 
25 root = Tk()
26 root.geometry('800x400')
27 root.title('Road Signs')
28 Button(root,text='QUIT',command=root.quit,bg='red',fg='white').pack()
29 
30 
31 MyButton = pto(Button,root)
32 CritButton = pto(MyButton,command=critCB,bg='white',fg='red')
33 WarnButton = pto(MyButton,command = warnCB,bg = 'goldenrod1')
34 ReguButton = pto(MyButton,command = infoCB,bg = 'white')
35 
36 for eachSign in SIGNS:
37     signType = SIGNS[eachSign]
38     cmd = '%sButton(text = %r%s).pack(fill = X,expand = True)' %(
39         signType.title(),eachSign,'.upper()' if signType == CRIT else '.title()'
40     )
41     eval(cmd)
42 
43 root.mainloop()