Entry

When and why should I use Intvar() etc?

When and how do I use the textvariable option?

Jun 20th, 2000 04:51
unknown unknown, richard_chamberlain

from Tkinter import *
root=Tk()
myIntVar = IntVar()
myStringVar= StringVar()
Label(root,textvariable=myStringVar).pack(side=TOP)
def setLabel():
    myStringVar.set(myIntVar.get())
Radiobutton(root,text="First Radiobutton",variable=myIntVar,value=1,
                    command=setLabel).pack(side=LEFT)
Radiobutton(root,text="Second Radiobutton",variable=myIntVar,value=2,
                    command=setLabel).pack(side=LEFT)
root.mainloop()

I'm using both IntVar and textvariable in this example.

I create new instances of Intvar and StringVar. I then create a label 
and assign the textvariable option to the instance of StringVar. I can 
now set the text of this label by called myStringVar.set('Hello') or get 
the text by myStringVar.get().

Next I've created two Radiobuttons and assigned their variable options 
to the instance of IntVar. I give them two separate values. Any changes 
to the radiobuttons will now be reflected in myIntVar.

I created a function called setLabel which uses the set and get methods 
of the instances. I then assign it to the label by called 
myStringVar.set(myIntVar.get()) which changes the value of the 
textvariable and the change is immediately reflected on the label.