Python, Tkinter,How to change GUI based on buttonclick

I am using Tkinter in a programming assignment and have the following problem. I want the user to enter the value in a textbox, and I want to add additional fields on the GUI based on the number entered in the textbox when he/she clicks the submit-button.

I tried to place code inside of the function 'displayText()', which is called when the submit-button is pressed; however, the GUI-related code that I placed inside of it was loaded when the window was loaded.

import tkinter

#When user clicks 开发者_运维知识库on button
def displayText():
    #DO CHANGE IN GUI

root = tkinter.Tk()
button = tkinter.Button(root, text="Submit", command=displayText())
button.pack()

root.mainloop()

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The problem is in this line of code:

button = tkinter.Button(root, text="Submit", command=displayText())

The command option takes a reference to a command. What you are doing instead is calling a command (displayText()) and giving the results of that command to the option. You need to remove the () so that the actual command to run is associated with the option, like so:

button = tkinter.Button(root, text="Submit", command=displayText)