python模块tkinter的variable

BooleanVar
DoubleVar
IntVar
StringVar

val = StringVar()
label = Label(text = "text...",textvariable = val)

# value
value = val.get()
val.set("new text ...")
# other
# mode is one of the "w","u","r"
trace(mode, callback)
trace_variable(mode, callback)
trace_vdelete(mode, observer name)
trace_vinfo()