Python偏函数应用举例

偏函数应用举例：路灯指示牌

1 1 #!/usr/bin/env python
2 2 # _*_coding:utf-8_*_
3 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 4 from functools import partial as pto
5 5 from tkinter import Tk, Button,X
6 6 from tkinter.messagebox import showinfo,showwarning,showerror
7 7 WARN = 'warn'
8 8 CRIT = 'crit'
9 9 REGU = 'regu'
1010 
1111 SIGNS = {
1212     'do not enter':CRIT,
1313     'railroad crossing':WARN,
1414     '55\nspeed limit':REGU,
1515     'wrong way': CRIT,
1616     'merging traffic': WARN,
1717     'one way': REGU,
1818 }
1919 
2020 critCB = lambda: showerror('Error','Error Button Pressed!')
2121 warnCB = lambda: showwarning('Warning','Warning Button Pressed!')
2222 infoCB = lambda: showinfo('Info','Info Button Pressed!')
2323 
2424 
2525 root = Tk()
2626 root.geometry('800x400')
2727 root.title('Road Signs')
2828 Button(root,text='QUIT',command=root.quit,bg='red',fg='white').pack()
2929 
3030 
3131 MyButton = pto(Button,root)
3232 CritButton = pto(MyButton,command=critCB,bg='white',fg='red')
3333 WarnButton = pto(MyButton,command = warnCB,bg = 'goldenrod1')
3434 ReguButton = pto(MyButton,command = infoCB,bg = 'white')
3535 
3636 for eachSign in SIGNS:
3737     signType = SIGNS[eachSign]
3838     cmd = '%sButton(text = %r%s).pack(fill = X,expand = True)' %(
3939         signType.title(),eachSign,'.upper()' if signType == CRIT else '.title()'
4040     )
4141     eval(cmd)
4242 
4343 root.mainloop()