Radiobutton

from tkinter import *

root = Tk()
v = IntVar()

LANGS=[
    ('Python',1),
    ('Perl',2),
    ('Ruby',3),
    ('Lua',4)
    ]
v = IntVar()
v.set(1)

for lang,num in LANGS:
    Radiobutton(root,text=lang,variable = v,value=num,indicatoron=False).pack(anchor= W,fill=X)
    #这里注意，variables其实是button本身的值，它等于谁，就决定了button的默认值
    #在这里设定了v ＝ 1，也即variable＝1，所以button默认就指向值为一的选项

root.mainloop()