def miles_to_km():
miles = float(miles_input.get())
km = miles * 1.609
kilometer_result_label.config(text=f"{km}")
给出的输出错误是:
miles = float(miles_input.get()) NameError: name 'miles_input' is not defined\
textvariable
需要 tk.StringVar()
、tk.IntVar()
或 tk.DoubleVar()