Distinguishing callbacks for different events when using the same function

Question

I am coding minesweeper in python turtle. I have made it generate 10x10 button layout using this script:

position_x = -400
position_y = -200
number_colum = 0
rows_buttons = []
for i in range(10):
 for i in range(10):
 rows_buttons.append([tk.Button(canvas.master, text="////", command=button_run)])
 canvas.create_window(position_x, position_y, window=rows_buttons[number_colum])
 number_colum += 1
 position_x += 40
 position_y += 40
 position_x += -400

However I am having trouble finding out which button was pressed (e.g. button at (2,3)). How can I code it so it's able to tell which one is which?

Here is the full code:

import random
import turtle
import tkinter as tk
screen=turtle.Screen() 
screen.bgcolor("light blue") 
screen.setup(1.0,1.0) 
screen.title("Turtle minesweeper")
canvas = screen.getcanvas()
def button_run():
 pass
position_x = -400
position_y = -200
number_colum = 0
rows_buttons = []
for i in range(10):
 for i in range(10):
 rows_buttons.append([tk.Button(canvas.master, text="////", command=button_run)])
 canvas.create_window(position_x, position_y, window=rows_buttons[number_colum])
 number_colum += 1
 position_x += 40
 position_y += 40
 position_x += -400
rows = []
for i in range(10):
 rows.append([0,0,0,0,0,0,0,0,0,0])
rows_descovered = []
for i in range(10):
 rows.append([0,0,0,0,0,0,0,0,0,0])
mines_maker = 10
while not mines_maker == 0:
 random_row_number = random.randint(0,9)
 random_colum_number = random.randint(0,9)
 random_row = rows[random_row_number]
 random_colum = random_row[random_colum_number]
 if random_row[random_colum] == 0:
 random_row[random_colum_number] = 1
 rows[random_row_number] = random_row
 mines_maker -= 1
 else:
 pass

I can't add variables at the end of the function, and I wish to not use mouse coordinates as it is just janky for me.

• Advaith: Try passing a lambda function to tk.Button, which calls button_run with an argument. This way, the same function can be reused for all the buttons
• ggorlen: Instead of editing FIXED IT: into the post, please post a self answer.

Answer 1

To reuse the same function for callbacks, functions must be used with default arguments. This is to ensure that the value used by the caller is a constant. If default arguments aren't used, Python will load the values for the variables at runtime, which will be a static value (since the loop has finished execution).

Here is a MWE. Note the command passed to the button uses a default argument.

#!/usr/bin/python3
import tkinter as tk
def callback(x, y):
 print("Hello from ({}, {})!".format(x, y))
root = tk.Tk()
for i in range(10):
 for j in range(10):
 tk.Button(text="{}, {}".format(i, j),
 command=lambda x=i, y=j: callback(x, y))\
 .grid(column=i, row=j)
root.mainloop()

• jackal: You could also use functools.partial rather than lambda