Beginners Problem! NameError on python tkinter

Question

New to python so this is probably a dumb question...

I want to say that if text1.get() == "1" then x = 0 and if text2.get() = "2" then y = 8 . Then I want a button that adds x and y .

from tkinter import *

new = Tk()
new.title("Lockdown?")
new.geometry("700x400")

text3=Entry(new, width = "60")
text3.place(rely=0.15)
if text3.get() == "":
        label9 = Label(new, text="required field", fg="red")
        label9.place(rely=0.17)
elif text3.get() == "1":
        x = "0"
elif text3.get() == "2":
        x = "1"
elif text3.get() == "10":
        x = "9"
else:
        label10 = Label(new, text = "Please use a number ranging from 1-10")
 
text4=Entry(new, width = "60")
text4.place(rely=0.26)
if text4.get() == "":
        label11 = Label(new, text="Required Field", fg = "red")
        label11.place(rely=0.19)
elif text4.get() == "7":
        y = "3"
elif text4.get() == "8":
        y = "2"
elif text4.get() == "9":
        y = "1"
elif text4.get() == "10":
        y = "0"
else:
        label11 = Label(new, text = "Please use a number ranging from 1-10")
      
def cmd3():
        label15 = Label(new, text = x + y)
        label15.place(rely=0.8)
        
btn3 = Button(new, text = "Submit Answers", command = cmd3, font=("Arial Bold", 25), bg = "white", fg = "black")
btn3.place(rely=0.71)   
new.mainloop()

Answer 1

GUI frameworks ( tkinter , PyQt , wxPython , etc., and in other languages) don't work like function input() . Entry doesn't wait for your data - it only inform mainloop what it has to display in window . And mainloop starts all - it displays window, etc. If you want to get value from Entry then you should do it in function assigned to Button .

---

My version with other changes

I use pack() instead of place() because it is simpler to organize widgets.

I create all labels at start (with empty text) and later I replace text in labels.

import tkinter as tk  # PEP8: `import *` is not preferred

# --- functions ---

def cmd3():
    # default value at start
    x = None
    y = None
    
    # remove previous text
    label1['text'] = ""
    label2['text'] = ""
    
    text = text1.get()
    
    if text == "":
        label1['text'] = "required field"
    elif text == "1":
        x = 0
    elif text == "2":
        x = 1
    elif text == "10":
        x = 9
    else:
        label1['text'] = "Please use a number ranging from 1-10"

    text = text2.get()
     
    if text == "":
        label2['text'] = "required field"
    elif text == "7":
        y = 3
    elif text == "8":
        y = 2
    elif text == "9":
        y = 1
    elif text == "10":
        y = 0
    else:
        label2['text'] = "Please use a number ranging from 1-10"
        
    print(x, y)

    # it can't be `if x and y:` because `0` will gives `False`
    if (x is not None) and (y is not None):
        label_result['text'] = str(x + y)

# --- main ---

new = tk.Tk()

# empty at start
label1 = tk.Label(new, text="", fg="red")
label1.pack()

text1 = tk.Entry(new, width="60")  # PEP8: arguments without spaces around `=`
text1.pack()

# empty at start
label2 = tk.Label(new, text="", fg="red")
label2.pack()

text2 = tk.Entry(new, width="60")  
text2.pack()
        
btn3 = tk.Button(new, text="Submit Answers", command=cmd3)
btn3.pack()   

# empty at start
label_result = tk.Label(new, text="", fg="green")
label_result.pack()

new.mainloop()