import tkinter as tk
my_w = tk.Tk()
from tkinter import messagebox as msg
my_w.geometry("500x500") # Size of the window
msg.showinfo("Title Here","Your Message here")
#messagebox.showerror("error","Error")
my_w.mainloop() # Keep the window open
Above window shows information only, we can collect user selection also. 
tkMessageBox.typeofmessage(title, message [, options]).
Show Message only :
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
msg.showerror("Title Here ","Your Message here ")
my_w.mainloop()
#showinfo
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
msg.showinfo("Title Here ","Your info message here ")
my_w.mainloop()
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
msg.showwarning("Title Here ","Your warning message here ")
my_w.mainloop()
We will ask user to select choice and we will capture the selected option through a variable.
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
my_var=msg.askokcancel("Title Here ","Your Choice ")
print(my_var) # Output True or False
my_w.mainloop()
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
my_var=msg.askyesno("Title Here ","Your Choice ")
print(my_var) # Output True or False
my_w.mainloop()
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
my_var=msg.askretrycancel("Title Here ","Your idea")
print(my_var) # Output True or False
my_w.mainloop()
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
my_var=msg.askyesnocancel("Title Here ","Your choice")
print(my_var) # Output True or False or None
my_w.mainloop()

yes , no or cancel
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
my_var=msg.askyesnocancel("Title Here ","Your choice",default='cancel')
# default = yes or no or cancel
print(my_var)
my_w.mainloop()
warning or info or question or error
import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("500x500") # Size of the window
my_var=msg.askyesnocancel("Title Here ","Your choice",icon='warning')
# icon = warning or error or information or question
print(my_var)
my_w.mainloop()

import tkinter as tk
from tkinter import messagebox as msg
my_w = tk.Tk()
my_w.geometry("300x200") # Size of the window
#my_var=tk.StringVar(my_w)
def show_msg(): # on click of the button b1
my_var=msg.askyesnocancel('Title Here', 'Message here')
print(my_var) # print at console
l1.config(text=str(my_var)) # display at Label
b1=tk.Button(my_w,text='Show Message',command=show_msg)
b1.grid(row=1,column=1,padx=30,pady=30)
my_font=('times',18,'bold')
l1=tk.Label(my_w,text='Output here',font=my_font,bg='yellow')
l1.grid(row=2,column=1)
my_w.mainloop()
The output will show as 0 or 1, to display as string saying True, False , None , yes, no We have to convert the same to string by using str()
l1.config(text=str(my_var)) # display at Label

def show_msg():
str1='Alex'
str2=44
m1="This is OK Mr {0} \n You R deleting id: {1}".format(str1,str2)
my_var=msg.askyesnocancel('Title Here', m1)
print(my_var)
l1.config(text=str(my_var))
Author & Instructor at plus2net
I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.