Python Text editor

from tkinter import Tk, scrolledtext, Menu, filedialog, END, messagebox, simpledialog
from tkinter import *
import os
import sys
import fileinput

def newFile():
    global is_saved
    if is_saved == len(textArea.get('1.0', END+'-1c')):
        textArea.delete('1.0', END)
        main_window.title("New File")
        is_saved = 0
    else:
        FileNotSaved()
        textArea.delete('1.0', END)
        main_window.title("New File")
        is_saved = 0


def openFile():
    global is_saved
    global file
    if is_saved == len(textArea.get('1.0', END+'-1c')):
        file = filedialog.askopenfile(parent=main_window, mode='rb', title="Please select a file:")
        data = file.read()
        textArea.delete('1.0', END)
        textArea.insert('1.0', data)
        file.close()
        main_window.title(file.name)
        is_saved = len(textArea.get('1.0', END+'-1c'))
    else:
        FileNotSaved()
        file = filedialog.askopenfile(parent=main_window, mode='rb', title="Please select a file:")
        data = file.read()
        textArea.delete('1.0', END)
        textArea.insert('1.0', data)
        file.close()
        main_window.title(file.name)
        is_saved = len(textArea.get('1.0', END+'-1c'))

def saveFileAs():
    global file
    file = filedialog.asksaveasfile(mode='w')
    data = textArea.get('1.0', END+'-1c')
    file.write(data)
    file.close()
    main_window.title(file.name)
    global is_saved
    is_saved = len(textArea.get('1.0', END+'-1c'))


def saveFile():
    global is_saved
    if file:
        fileToOpen = open(file.name, 'w')
        data = textArea.get('1.0', END+'-1c')
        fileToOpen.write(data)
        fileToOpen.close()
        is_saved = len(textArea.get('1.0', END+'-1c'))
    else:
        saveFileAs()

def FileNotSaved():
    if messagebox.askyesno("Save?", "Do you want to save first?"):
        saveFile()

def Exit():
    if is_saved == len(textArea.get('1.0', END+'-1c')):
        main_window.destroy()
    else:
        FileNotSaved()
        main_window.destroy()

def Undo():
    textArea.edit_undo()

def Redo():
    textArea.edit_redo()

def Replace():
    input = simpledialog.askstring("Find and Replace", "Enter text to find...")
    replace = simpledialog.askstring("Find and Replace", "Enter text to replace with...")
    text = textArea.get('1.0', END+'-1c')
    if input in text:
        text = text.replace(input, replace)
        textArea.delete('1.0', END)
        textArea.insert('1.0', text)







def Find():
    text = textArea.get('1.0', END+'-1c').lower()
    input = simpledialog.askstring("Find", "Enter text to find...").lower()
    startindex = []
    endindex = []
    lines = 0
    if input in text:
        text = textArea.get('1.0', END+'-1c').lower().splitlines()
        for var in text:
            character = text[lines].index(input)
            start = str(lines + 1) + '.' + str(character)
            startindex.append(start)
            end = str(lines + 1) + '.' + str(character + int(len(input)))
            endindex.append(end)
            textArea.tag_add('select', startindex[lines], endindex[lines])
            lines += 1

    textArea.tag_config('select', background = 'green')


def Finds():
    textArea.tag_add('select', '1.0', '2.0')
    textArea.tag_config('select', foreground='green')


def Findt():
    lines = 0
    list = []
    list2 = ['first line', 'why', 'third line']
    for item in list2:
        list.append(list2[lines])
        lines += 1
    print(list)





is_saved = 0
file = ""

main_window = Tk()
main_window.title("New File")
textArea = scrolledtext.ScrolledText(main_window, width=100, height=30)
menu = Menu(main_window)
main_window.config(menu=menu)
fileMenu = Menu(menu, tearoff=False)
menu.add_cascade(label='File', menu=fileMenu)
fileMenu.add_command(label='New', command=newFile)
fileMenu.add_separator()
fileMenu.add_command(label='Open', command=openFile)
fileMenu.add_command(label='Save As', command=saveFileAs)
fileMenu.add_command(label='Save', command=saveFile)
fileMenu.add_separator()
fileMenu.add_command(label='Exit', command=Exit)



editMenu = Menu(menu, tearoff=False)
menu.add_cascade(label='Edit', menu=editMenu)
editMenu.add_command(label='Undo', command=Undo)
editMenu.add_command(label='Redo', command=Redo)
editMenu.add_separator()
editMenu.add_command(label='Cut', command=lambda: textArea.event_generate('<Control-x>'))
editMenu.add_command(label='Copy', command=lambda: textArea.event_generate('<Control-c>'))
editMenu.add_command(label='Paste', command=lambda: textArea.event_generate('<Control-v>'))
editMenu.add_separator()
editMenu.add_command(label='Find', command =Find)
editMenu.add_command(label='Replace', command=Replace)






textArea.pack()
main_window.mainloop()