global question (python)

I have the code:

from Tkinter import *
admin = Tk()
a = 1

def up():
    global a
    a += 1

def upp():
    up()
    print a
print 'its ',a
buttton = Button(admin, text='up', command=upp)
buttton.pack()
mainloop()

I w开发者_运维问答ant to have the "its ",a go up each time i press the button. so kind of replay the code so that, its # would go up by one each time...help

I tested this:

from Tkinter import *
import itertools

admin = Tk()
a = itertools.count(1).next


def upp():
    print a()

buttton = Button(admin, text='up', command=upp)
buttton.pack()
mainloop()

This will start a at a value of 1 and each time its printed it will add one more. So the first time you press it, it will display 1 in standard out.

Replace

def upp():
    up()
    print a
print 'its ',a
buttton = Button(admin, text='up', command=upp)
buttton.pack()
mainloop()

with

def upp():
    up()
    print 'its ', a
buttton = Button(admin, text='up', command=upp)
buttton.pack()
mainloop()

and it works as you want.

Update: Note that you dont need two functions. A simplified version:

from Tkinter import *
admin = Tk()
a = 0

def upp():
    global a
    a += 1
    print 'its ', a

buttton = Button(admin, text='up', command=upp)
buttton.pack()
mainloop()

anyway global variables should be avoided (see Alan answer for a better solution)