from Tkinter import *
global edt1
def calc():
	value = int(str(edt1.get()))
	i = 0
	for i in range(value):
		print i

window = Tk()
lbl1=Label(window, text='How many iterations?')
lbl1.pack(side=TOP)
edt1=Entry(name='text')
edt1.pack(expand = YES, fill = BOTH)
btn1=Button(window, text='Calculate', command=calc())
bt1.pack(side=BOTTOM)
window.mainloop()